View Filing Data

Document and Entity Information - $ / shares	6 Months Ended
Document and Entity Information - $ / shares	Jun. 30, 2013	Aug. 01, 2013
Document and Entity Information
Entity Registrant Name	Esperion Therapeutics, Inc.
Entity Central Index Key	0001434868
Document Type	10-Q
Document Period End Date	Jun. 30, 2013
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		15,357,413
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Entity Listing, Par Value Per Share	$ 0.001

Condensed Balance Sheets - USD ($)	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 16,626,859	$ 6,511,521
Deferred offering costs	2,449,637
Prepaid clinical development costs	212,612	367,216
Other prepaid and current assets	70,907	150,325
Assets held for sale	29,108	109,344
Total current assets	19,389,123	7,138,406
Property and equipment, net	89,274	120,210
Intangible assets	55,740	53,825
Total assets	19,534,137	7,312,441
Current liabilities:
Short term borrowings with related parties, net of debt discount		15,241,007
Accrued interest		738,192
Accounts payable	1,655,762	476,277
Accrued clinical development costs	923,809	242,171
Warrant liabilities	2,852,188	265,323
Other accrued liabilities	1,212,666	210,329
Total current liabilities	6,644,425	17,173,299
Long-term debt		7,528,845
Total liabilities	6,644,425	24,702,144
Stockholders' deficit:
Common stock, $0.001 par value; 120,000,000 shares authorized as of June 30, 2013 and 50,000,000 shares authorized as of December 31, 2012, respectively; 396,414 shares issued and 372,079 outstanding at June 30, 2013 and 346,478 shares issued and outstanding at December 31, 2012	396	346
Additional paid-in capital	796,508	609,976
Deficit accumulated during the development stage	(53,135,278)	(41,975,025)
Total stockholders' (deficit) equity	(52,338,374)	(41,364,703)
Total liabilities, convertible preferred stock and stockholders' (deficit) equity	19,534,137	7,312,441
Series A preferred stock
Convertible preferred stock:
Convertible preferred stock	57,478,555	23,975,000
Series A-1 preferred stock
Convertible preferred stock:
Convertible preferred stock	$ 7,749,531

Condensed Balance Sheets (Parenthetical) - USD ($)	Jun. 30, 2013	Dec. 31, 2012
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	120,000,000	50,000,000
Common stock, shares issued	396,414	346,478
Common stock, shares outstanding	372,079	346,478
Series A preferred stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	59,538,092	34,785,000
Preferred stock, shares issued	57,598,092	23,975,000
Preferred stock, shares outstanding	57,598,092	23,975,000
Preferred stock, aggregate liquidation preference (in dollars)	$ 57,598,092	$ 23,975,000
Series A-1 preferred stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	7,862,283	7,862,283
Preferred stock, shares issued	6,750,000	0
Preferred stock, shares outstanding	6,750,000	0
Preferred stock, aggregate liquidation preference (in dollars)	$ 7,803,000	$ 0

Condensed Statements of Operations - USD ($)	3 Months Ended		6 Months Ended		65 Months Ended
Condensed Statements of Operations - USD ($)	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Condensed Statements of Operations
Grant income					$ 244,479
Operating expenses:
Research and development	$ 3,100,422	$ 2,330,223	$ 5,193,015	$ 3,887,434	32,606,876
General and administrative	1,171,425	533,658	2,422,844	1,166,030	13,872,540
Acquired in-process research and development					85,612
Total operating expenses	4,271,847	2,863,881	7,615,859	5,053,464	46,565,028
Loss from operations	(4,271,847)	(2,863,881)	(7,615,859)	(5,053,464)	(46,320,549)
Interest expense	(108,357)	(303,167)	(936,580)	(563,595)	(4,320,696)
Change in fair value of warrant liability	(2,544,907)		(2,586,865)		(2,554,498)
Other income (expense), net	4,035	894	(20,949)	1,953	60,465
Net loss	$ (6,921,076)	$ (3,166,154)	$ (11,160,253)	$ (5,615,106)	$ (53,135,278)
Net loss per common share (basic and diluted) (in dollars per share)	$ (19.82)	$ (9.94)	$ (32.09)	$ (17.92)
Weighted-average shares outstanding (basic and diluted)	349,170	318,654	347,831	313,258

Condensed Statements of Cash Flows - USD ($)	6 Months Ended		65 Months Ended
Condensed Statements of Cash Flows - USD ($)	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Operating activities
Net loss	$ (11,160,253)	$ (5,615,106)	$ (53,135,278)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	49,139	71,956	1,426,310
Amortization of debt discount and beneficial conversion	458,993		575,981
Amortization of debt issuance costs	18,533	4,592	33,911
Change in fair value of warrant liability	2,586,865		2,554,498
Noncash interest expense on convertible notes	459,055	563,595	3,726,092
Write-off of acquired in-process research and development			85,612
Stock-based compensation expense	153,412	31,299	410,520
Common stock issued in license agreement			4,400
Loss related to assets held for sale	29,000		324,701
Gain on sale of assets	(5,029)	(1,949)	(23,488)
Changes in assets and liabilities:
Prepaids and other assets	213,574	(394,930)	(323,196)
Accounts payable	287,695	11,641	763,972
Other accrued liabilities	1,102,900	(203,697)	1,555,397
Net cash used in operating activities	(5,806,116)	(5,532,599)	(42,020,568)
Investing activities
Purchases of short-term investments			(31,569,166)
Proceeds from maturities of short-term investments			31,515,350
Cash obtained in stock acquisition			2,500,000
Proceeds from sale of assets	56,265	4,500	807,464
Purchase of property and equipment	(18,203)	(10,668)	(285,762)
Other investing			50,626
Net cash (used in) provided by investing activities	38,062	(6,168)	3,018,512
Financing activities
Proceeds from issuance of common stock	123,245	17,362	184,068
Proceeds from issuance of preferred stock, net of issuance costs	16,826,994		40,801,994
Payments for offering costs in connection with initial public offering	(1,066,847)		(1,066,847)
Proceeds from warrant issuance			297,690
Proceeds from debt issuance with related parties		6,000,000	15,412,010
Net cash provided by financing activities	15,883,392	6,017,362	55,628,915
Net increase (decrease) in cash and cash equivalents	10,115,338	478,595	16,626,859
Cash and cash equivalents at beginning of period	6,511,521	1,571,084
Cash and cash equivalents at end of period	16,626,859	$ 2,049,679	16,626,859
Supplemental disclosure of cash flow information:
Deferred offering costs not yet paid	1,382,790		1,382,790
Convertible promissory note
Supplemental disclosure of cash flow information:
Conversion of convertible debt, including accrued interest, into preferred stock	16,623,092		16,623,092
Pfizer note
Supplemental disclosure of cash flow information:
Conversion of convertible debt, including accrued interest, into preferred stock	$ 7,803,000		$ 7,803,000

The Company and Basis of Presentation	6 Months Ended
The Company and Basis of Presentation	Jun. 30, 2013
The Company and Basis of Presentation
The Company and Basis of Presentation	1. The Company and Basis of Presentation The Company is a biopharmaceutical company focused on the research, development and commercialization of therapies for the treatment of patients with elevated levels of low-density lipoprotein cholesterol (LDL-C) and other cardiometabolic risk factors. ETC-1002, the Company’s lead product candidate, is a novel, first in class, orally available, once-daily small molecule therapy designed to target known lipid and carbohydrate metabolic pathways to reduce levels of LDL-C and to avoid side effects associated with existing LDL-C lowering therapies. The Company owns the exclusive worldwide rights to ETC-1002 and its other product candidates. HDL Therapeutics, Inc. (HDL) was incorporated in the state of Delaware on January 22, 2008. On April 28, 2008, HDL acquired all of the capital stock of Esperion Therapeutics, Inc. (Esperion), a wholly owned subsidiary of Pfizer Inc. On May 5, 2008, Esperion was merged with and into HDL and the Company assumed the name Esperion Therapeutics, Inc. (the Company). Its facilities are located in Plymouth, Michigan. The Company’s primary activities since incorporation have been recruiting personnel, conducting research and development activities, including pre-clinical and clinical testing, performing business and financial planning, and raising capital. Accordingly, the Company is considered to be in development stage. The Company is subject to the risks associated with a development stage entity, which includes the need to: research, develop, and clinically test potential therapeutic products; obtain regulatory approvals for its products and commercialize them, if approved; expand its management and scientific staff; and finance its operations with an ultimate goal of achieving profitable operations. The Company has sustained operating losses since inception and expects such losses to continue over the foreseeable future. Management plans to continue to finance operations with a combination of public and private equity issuances, debt arrangements, collaborations and strategic and licensing arrangements. If adequate funds are not available, the Company may not be able to continue the development of its current or future product candidates, or to commercialize its current or future product candidates, if approved. Basis of Presentation The accompanying condensed financial statements are unaudited and were prepared by the Company in accordance with generally accepted accounting principles in the United States of America (GAAP). In the opinion of management, the Company has made all adjustments, which include only normal recurring adjustments necessary for a fair statement of the Company’s financial position and results of operations for the interim periods presented. Certain information and disclosures normally included in the annual financial statements prepared in accordance with GAAP have been condensed or omitted. These condensed financial statements should be read in conjunction with the audited financial statements and accompanying notes for the year ended December 31, 2012 included in the Company’s final prospectus dated June 25, 2013 filed pursuant to Rule 424(b) under the Securities Act of 1933, as amended, with the Securities and Exchange Commission on June 26, 2013. The results for the three and six months ended June 30, 2013 are not necessarily indicative of the results to be expected for a full year, any other interim periods or any future year or period. Reverse Stock Split On June 11, 2013, in connection with its initial public offering (the IPO), the Company effectuated a 1-for-6.986 reverse stock split of its outstanding common stock, which was approved by the Company’s board of directors on June 5, 2013. The reverse stock split resulted in an adjustment to the Series A preferred stock and Series A-1 preferred stock conversion prices to reflect a proportional decrease in the number of shares of common stock to be issued upon conversion. The accompanying financial statements and notes to the financial statements give effect to the reverse stock split for all periods presented. The shares of common stock retained a par value of $0.001 per share. Accordingly, the stockholders’ deficit reflects the reverse stock split by reclassifying from “common stock” to “Additional paid-in capital” in an amount equal to the par value of the decreased shares resulting from the reverse stock split.

- Definition

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

+ References

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+ Details

Summary of Significant Accounting Policies	6 Months Ended
Summary of Significant Accounting Policies	Jun. 30, 2013
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Cash and Cash Equivalents The Company invests its excess cash in bank deposits, money market accounts, and short-term investments. The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash equivalents are reported at fair value. Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to concentrations of credit risk. The Company has established guidelines for investment of its excess cash and believes the guidelines maintain safety and liquidity through diversification of counterparties and maturities. Segment Information The Company views its operations and manages its business in one operating segment, which is the business of researching, developing and commercializing therapies for the treatment of patients with elevated levels of low-density lipoprotein cholesterol and other cardiometabolic risk factors. Fair Value of Financial Instruments The Company’s financial instruments consist principally of cash and cash equivalents, other current assets, accounts payable and accrued liabilities that approximate their carrying value. Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation. Depreciation is provided using the straight-line method over the estimated useful lives of the respective assets, generally three to ten years. Leasehold improvements are amortized over the lesser of the lease term or the estimated useful lives of the related assets. Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition are less than its carrying amount. The impairment loss, if recognized, would be based on the excess of the carrying value of the impaired asset over its respective fair value. Excluding impairment losses recorded on assets held for sale, no other impairment losses have been recorded through June 30, 2013. Research and Development Research and development expenses consist of costs incurred to further the Company’s research and development activities and include salaries and related benefits, costs associated with pre-clinical studies and trials, non-clinical activities (such as toxicology studies), regulatory activities, manufacturing activities to support clinical activities, research-related overhead expenses, and fees paid to external service providers that conduct certain research and development, clinical, and manufacturing activities on behalf of the Company. Research and development costs are expensed as incurred. In-Process Research and Development In April 2008, the Company acquired certain tangible research and development assets and intellectual property from Pfizer Inc. (Pfizer). As the acquired in-process research and development had not reached technological feasibility and had no alternative future uses in connection with this asset and intellectual property acquisition and the related purchase price allocation, the Company expensed $85,612 as in-process research and development costs in 2008. Accrued Clinical Development Costs Outside research costs are a component of research and development expense. These expenses include fees paid to contract research organizations and other service providers that conduct certain clinical and product development activities on behalf of the Company. Depending upon the timing of payments to the service providers, the Company recognizes prepaid expenses or accrued expenses related to these costs. These accrued or prepaid expenses are based on management’s estimates of the work performed under service agreements, milestones achieved and experience with similar contracts. The Company monitors each of these factors and adjusts estimates accordingly. Income Taxes The Company utilizes the liability method of accounting for income taxes as required by ASC 740, Income Taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and the tax basis of assets and liabilities and are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company has incurred operating losses since inception. Accordingly, it is not more likely than not that the Company will realize deferred tax assets and as such, it has recorded a full valuation allowance. Warrant Liability The Company accounts for its warrants issued in connection with its various financing transactions based upon the characteristics and provisions of the instrument. Warrants classified as derivative liabilities are recorded on the Company’s balance sheet at their fair value on the date of issuance and are marked-to-market on each subsequent reporting period, with the fair value changes recognized in the statement of operations. The warrants are measured using the Black-Scholes option-pricing model subsequent to the pricing of the Company’s IPO and a Monte Carlo valuation model for previous periods which are based, in part, upon inputs where there is little or no market data, requiring the Company to develop its own independent assumptions. The Company will continue to adjust the liability for changes in the fair value of these warrants until the earlier of the exercise of the warrants, the expiration of the warrants, or until such time as the warrants are no longer determined to be derivative instruments. Stock-Based Compensation The Company accounts for stock-based compensation in accordance with the provisions of ASC 718, Compensation—Stock Compensation. Accordingly, compensation costs related to equity instruments granted are recognized over the requisite service periods of the awards on a straight-line basis at the grant-date fair value calculated using a Black-Scholes option pricing model. Additionally, under the provisions of ASC 718, the Company is required to include an estimate of the number of awards that will be forfeited in calculating compensation costs. Any changes to the estimated forfeiture rates are accounted for prospectively. Stock-based compensation arrangements with non-employees are recognized at the grant-date fair value and then re-measured at each reporting period. Expense is recognized during the period the related services are rendered.

Fair Value Measurements

6 Months Ended

Jun. 30, 2013

Fair Value Measurements

Fair Value Measurements

5. Fair Value Measurements

The Company follows accounting guidance that emphasizes that fair value is a market-based measurement, not an entity-specific measurement. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” Fair value measurements are defined on a three level hierarchy:

Level 1 inputs:	Quoted prices for identical assets or liabilities in active markets;

Level 2 inputs:	Observable inputs other than Level 1 prices, such as quoted market prices for similar assets or liabilities or other inputs that are observable or can be corroborated by market data; and

Level 3 inputs:	Unobservable inputs that are supported by little or no market activity and require the reporting entity to develop assumptions that market participants would use when pricing the asset or liability.

The following table presents the Company’s financial assets and liabilities that have been measured at fair value on a recurring basis:

Description	Total		Level 1		Level 2		Level 3
June 30, 2013
Assets:
Money market fund	$	16,558,101	$	16,558,101	$	—	$	—
Total assets at fair value	$	16,558,101	$	16,558,101	$	—	$	—
Liabilities:
Warrants	$	2,852,188	$	—	$	—	$	2,852,188
Total liabilities at fair value	$	2,852,188	$	—	$	—	$	2,852,188

December 31, 2012
Assets:
Money market fund	$	6,357,542	$	6,357,542	$	—	$	—
Total assets at fair value	$	6,357,542	$	6,357,542	$	—	$	—
Liabilities:
Warrants	$	265,323	$	—	$	—	$	265,323
Total liabilities at fair value	$	265,323	$	—	$	—	$	265,323

There were no transfers between Levels 1, 2 or 3 during the six months ended June 30, 2013 or June 30, 2012.

The following table summarizes the changes in the fair value of the Company’s Level 3 warrant liabilities the six month period ended June 30, 2013:

	Warrant Liability
Level 3 Liabilities:
As of December 31, 2012	$	265,323
Change in fair value	2,586,865
As of June 30, 2013	$	2,852,188

Fair Value Measurements on a Nonrecurring Basis

In addition to items that are measured at fair value on a recurring basis, the Company also measures assets held for sale at the lower of its carrying amount or fair value on a nonrecurring basis. During the six months ended June 30, 2013, the Company recognized an impairment loss of $27,000 based on recent purchase offers. The Company recognized $214,393 of impairment expense related to the assets held for sale in the period from inception through June 30, 2013. The fair value of assets held for sale was estimated using a market approach, considering the estimated fair value for other comparable equipment which are Level 3 inputs.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Convertible Preferred Stock and Stockholders' Deficit

6 Months Ended

Jun. 30, 2013

Convertible Preferred Stock and Stockholders' Deficit

Convertible Preferred Stock and Stockholders' Deficit

6. Convertible Preferred Stock and Stockholders’ Deficit

On January 22, 2008, HDL was incorporated in the state of Delaware with 1,000 shares of authorized common stock. In April 2008, the Board of Directors approved an amended and restated certificate of incorporation. The amendment increased HDL’s authorized number of shares of common stock to a total of 44,025,145 and authorized two new series of preferred stock designated as Series A and Series A-1 preferred stock consisting of 33,250,000 shares of Series A preferred stock and 6,475,145 shares of Series A-1 preferred stock. In April 2008, HDL sold 286,286 shares of common stock and 10,000,000 shares of Series A preferred stock in a private offering (the Initial Financing), raising net proceeds of $200 and $10,000,000, respectively. In the Initial Financing, the Company converted an outstanding promissory note in the principal amount of $250,000 from an officer of the Company into 250,000 shares of Series A preferred stock.

As a result of commencing Phase 1 clinical trials in December 2009, the Company issued 6,000,000 additional shares of Series A preferred stock, raising net proceeds of $6,000,000 in January 2010 (Second Tranche Shares in the Initial Financing agreement).

In April 2010, the Company issued an additional 1,000,000 shares of Series A preferred stock to an officer and new investors for $1,000,000 in net proceeds. In connection with this sale, the Initial Financing agreement was amended to allow for the additional issuance of shares. The Company also amended its certificate of incorporation to increase its number of authorized shares to 45,025,145 shares of common stock and 40,725,145 shares of preferred stock, including 34,250,000 shares of Series A preferred stock and 6,475,145 shares of Series A-1 preferred stock.

In November 2010, the Company issued an additional 25,000 shares of Series A preferred stock to an officer of the Company in exchange for $25,000.

As a result of commencing Phase 2a clinical studies in December 2010, the Company issued 6,700,000 shares of Series A preferred stock, raising net proceeds of $6,700,000 in January 2011 (Third Tranche Shares in the Initial Financing agreement). The Company also amended its certificate of incorporation to increase the number of authorized shares to 50,000,000 shares of common stock and 41,682,329 shares of preferred stock, including 34,785,000 shares of Series A preferred stock and 6,897,329 shares of Series A-1 preferred stock.

In September 2012, the Company amended its certificate of incorporation to increase the number of authorized preferred shares to 42,647,283, including 34,785,000 shares of Series A preferred stock and 7,862,283 shares of Series A-1 preferred stock.

As of December 31, 2012, the Company did not have sufficient preferred and common shares authorized under its certificate of incorporation to permit the conversion of the outstanding convertible promissory notes issued during 2012. Pursuant to the terms of the note purchase agreements, in the event any or all of the notes were to be converted, the purchasers and the Company agreed to take all action necessary to amend the certificate of incorporation to increase the number of authorized shares of Series A preferred stock and common stock to permit such conversion. The Company subsequently amended its certificate of incorporation to increase the number of shares of Series A preferred stock authorized to 41,636,970 and number of shares of common stock authorized to 56,519,253 in connection with the conversion of the notes on February 12, 2013 into 16,623,092 shares of Series A preferred stock.

On April 10, 2013, the Company amended its certificate of incorporation to increase the number of shares of Series A preferred stock authorized to 59,538,092 and the number of shares of common stock authorized 75,220,375.

On April 19, 2013, the Company issued and sold an aggregate of 17,000,000 shares of Series A preferred stock at a price of $1.00 for proceeds of $16,880,463, which is net of issuance costs of $119,537, to funds affiliated with Longitude Capital and certain existing investors. Each share of Series A preferred stock issued in the financing was convertible into 0.143 shares of common stock as of June 30, 2013. Upon the closing of the financing, Patrick Enright of Longitude Capital became a member of the board of directors.

On May 29, 2013, the Company entered into a stock purchase agreement with Pfizer Inc. and issued and sold 6,750,000 shares of Series A-1 preferred stock at a price of $1.1560 per share. The purchase price was paid through the cancellation of all outstanding indebtedness, including accrued interest, under the Pfizer convertible promissory note, which had an aggregate balance, including accrued interest, of $7,803,000 as of May 29, 2013. Each share of Series A-1 preferred stock issued in the agreement was convertible into 0.124 shares of common stock as of June 30, 2013.

On June 11, 2013 the Company amended its certificate of incorporation to increase the number of shares of common stock authorized to 120,000,000.

Convertible Preferred Stock

As of June 30, 2013 and December 31, 2012, the Company had authorized a total of 67,400,375 and 42,647,283 shares of preferred stock, respectively, designated in various series. The preferred stock designated as Series A and Series A-1 is summarized as follows:

	June 30, 2013
	Shares Designated	Liquidation Preference Per Share		Shares Issued and Outstanding
Series A	59,538,092	$	1.00	57,598,092
Series A-1	7,862,283	1.16		6,750,000
	67,400,375	$	1.02	64,348,092

	December 31, 2012
	Shares Designated	Liquidation Preference Per Share		Shares Issued and Outstanding
Series A	34,785,000	$	1.00	23,975,000
Series A-1	7,862,283	—		—
	42,647,283	$	1.00	23,975,000

Voting

The holders of preferred stock had various rights and preferences. Each share of Series A and Series A-1 preferred stock had certain voting rights equal to the number of shares of common stock into which it was convertible and voted together as one class with the common stock.

A separate vote of a majority of the Series A preferred stock, equal to the number of shares of common stock into which it was convertible, was required for certain activities, including certain issuances of common stock; for any redemption, repurchase, dividend, or other distribution with respect to the common stock; any agreement by the Company or its stockholders regarding certain mergers or consolidations of the Company; a sale of all or substantially all of the assets of the Company; or any redemption, repurchase, dividend, or other distribution with respect to any shares of preferred stock.

As the Series A and Series A-1 preferred stock could have been redeemed in a “deemed liquidation” in the event of a change of control and the redemption features were considered to be outside the control of the Company, all shares of Series A preferred stock have been presented outside of permanent equity in accordance with ASC 480.

Liquidation

In the event of any liquidation, dissolution, or winding-up of the Company, including a merger, acquisition, or sale of assets where the holders of the Company’s common stock and preferred stock owned less than 50% of the resulting voting power of the surviving entity, the holders of Series A preferred stock were entitled to receive prior and in preference to any distribution of the assets of the Company to the holders of Series A-1 preferred stock and common stock, an amount equal to $1.00 for each share of Series A preferred stock held, plus any declared but unpaid dividends. After payment of the full liquidation preference to holders of Series A preferred stock, but prior to any distribution or payment to holders of common stock, the holders of Series A-1 preferred were entitled to receive a distribution equal to the original issue price of a share of Series A-1 preferred stock plus any declared but unpaid dividends. After payment of the full liquidation preference(s) to the Series A and Series A-1 stockholders, the remaining assets legally available for distribution were distributed ratably to the holders of common stock and preferred stock on an as if converted to common stock basis.

Dividends

Holders of Series A and Series A-1 preferred stock, in preference to the holders of common stock, were entitled to receive cash dividends at the rate of eight percent of the respective original issue price per annum on each outstanding preferred share on a pari passu basis. Such dividends were payable only when, as and if declared by the Board of Directors and were non-cumulative. There were no dividends declared, accrued or paid during the period from inception through December 31, 2012 or the six months ended June 30, 2013.

Conversion

Any share of Series A or Series A-1 preferred stock could have been converted at the option of the holder at any time into shares of common stock at the Series A preferred conversion price or the Series A-1 preferred conversion price, respectively, then in effect.

Each share of Series A and Series A-1 preferred stock shall have been automatically converted into shares of common stock based upon the then-effective Series A preferred conversion price and the Series A-1 preferred conversion price, respectively, upon the affirmative election of the holders of at least 60% of the outstanding shares of the Series A preferred stock and Series A-1 preferred stock voting as a single class.

Each share of Series A preferred stock shall have automatically converted into shares of common stock based upon the effective Series A preferred conversion price upon (i) the affirmative election of the holders of at least two-thirds of the outstanding shares of the Series A preferred stock; (ii) the Company’s sale of its common stock in a firmly underwritten public offering in which the per share price is at least three times the Series A original issue price adjusted for stock splits, dividends, recapitalizations, and the like, and which would result in gross proceeds to the Company of at least $40 million (prior to deducting underwriting discounts and commissions); or (iii) the affirmative election of at least a majority of the outstanding shares of the Series A preferred stock following the closing of a firmly underwritten public offering that covered the offer and sale of common stock for the Company that did not meet the three times original issue price or gross proceeds requirements above. Upon an automatic conversion, any declared and unpaid dividends were to be paid to the holders of Series A preferred stock.

Each share of Series A-1 preferred stock shall have automatically converted into shares of common stock based upon the effective Series A-1 preferred conversion price upon the Company’s sale of its common stock in a firmly underwritten public offering which results in gross proceeds to the Company of at least $25 million (prior to underwriting discounts and commissions). Upon an automatic conversion, any declared and unpaid dividends shall have been paid to the holders of Series A-1 preferred stock.

The Series A preferred conversion rate and Series A-1 preferred conversion rate was the $1.00 Series A original issue price, divided by the Series A preferred conversion price, initially set at $6.986, or 0.143 common shares. The Series A preferred conversion price could have been adjusted in connection with certain dilutive events; however, there were no such adjustments.

The Company had convertible debt, convertible preferred stock and warrants, all of which were convertible into Series A and Series A-1 preferred stock. Additionally, the Company has stock options outstanding. The following table presents the number of common shares which could have been issuable upon the conversion of convertible instruments or exercise of options at June 30, 2013 and December 31, 2012:

	June 30, 2013	December 31, 2012
Convertible preferred stock	9,210,999	3,431,865
Warrants for preferred stock	277,690	277,690
Common shares under option	706,040	211,500
Convertible debt	—	3,430,723
Total shares issuable upon conversion or exercise	10,194,729	7,351,778

Stock Compensation

6 Months Ended

Jun. 30, 2013

Stock Compensation

Stock Compensation

7. Stock Compensation

2008 Incentive Stock Option and Restricted Stock Plan

The 2008 Incentive Stock Option and Restricted Stock Plan (the 2008 Plan), administered by the Board of Directors or a committee appointed by the Board of Directors. The 2008 Plan provides for the granting of stock options and restricted stock to employees and nonemployees of the Company. Options granted under the 2008 Plan may either be incentive stock options (ISOs), restricted stock awards (RSAs) or nonqualified stock options (NQSOs). Stock options and restricted stock grants may be granted to employees, directors and consultants. Stock awards under the 2008 Plan may be granted for up to ten years from the adoption of the 2008 Plan and the vesting of options granted or restricted awards given will be determined individually with each option grant. Generally, 25 percent of the granted amount vest upon the first anniversary of the option grant with the remainder vesting ratably on the first day of each calendar quarter for the following three years. Stock options have a 10 year life and expire if not exercised within that period, or if not exercised within 90 days of cessation of employment with the Company. Upon closing of the Company’s initial public offering, 54,129 shares reserved and not then subject to outstanding options were transferred to the 2013 Plan, and no further awards will be made under the 2008 Plan.

2013 Stock Option and Incentive Plan

On June 7, 2013, the Company’s stockholders approved the 2013 Stock Option and Incentive Plan (the 2013 Plan), which became effective on June 25, 2013. The number of shares of stock reserved and available for issuance under the 2013 Plan is the sum of (i) 1,100,000, plus (ii) 54,129 shares originally reserved under the 2008 Plan that became available for issuance under the 2013 Plan upon completion of the Company’s initial public offering, plus (iii) the shares underlying any awards granted under the 2008 Plan that are forfeited, canceled, held back upon the exercise of an option or settlement of an award to cover the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of stock or otherwise terminated (other than be exercise). Additionally, on January 1, 2014 and each January 1 thereafter, the number of shares reserved and available for issuance under the 2013 Plan shall be cumulatively increased by two and a half percent of the number of shares issued and outstanding on the immediately preceding December 31 or such lesser number of shares as determined by the plan administrator.

The following table summarizes the activity relating to the Company’s options to purchase common stock for the six months ended June 30, 2013:

	Number of Options		Weighted-Average Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value

Outstanding at December 31, 2012	211,500		$	1.43	7.5	$	141,389
Granted	545,549		$	3.23
Forfeited or expired	(1,073	)	$	1.54
Exercised	(49,936	)	$	2.47
Outstanding at June 30, 2013	706,040		$	2.74	9.0	$	8,018,165

The following table summarizes information about the Company’s stock option plan as of June 30, 2013 and December 31, 2012:

	Number of Options	Weighted-Average Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Vested and expected to vest at June 30, 2013	674,040	$	2.73	9.0	$	7,662,092
Exercisable at June 30, 2013	540,126	$	2.15	8.9	$	6,453,501

As of June 30, 2013, there was approximately $1,100,944 of unrecognized compensation cost related to unvested options, adjusted for forfeitures, which will be recognized over a weighted-average period of approximately 3.1 years.

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2013
Summary of Significant Accounting Policies
Cash and Cash Equivalents	Cash and Cash Equivalents The Company invests its excess cash in bank deposits, money market accounts, and short-term investments. The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash equivalents are reported at fair value.
Concentration of Credit Risk	Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to concentrations of credit risk. The Company has established guidelines for investment of its excess cash and believes the guidelines maintain safety and liquidity through diversification of counterparties and maturities.
Segment Information	Segment Information The Company views its operations and manages its business in one operating segment, which is the business of researching, developing and commercializing therapies for the treatment of patients with elevated levels of low-density lipoprotein cholesterol and other cardiometabolic risk factors.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments consist principally of cash and cash equivalents, other current assets, accounts payable and accrued liabilities that approximate their carrying value.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation. Depreciation is provided using the straight-line method over the estimated useful lives of the respective assets, generally three to ten years. Leasehold improvements are amortized over the lesser of the lease term or the estimated useful lives of the related assets.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition are less than its carrying amount. The impairment loss, if recognized, would be based on the excess of the carrying value of the impaired asset over its respective fair value. Excluding impairment losses recorded on assets held for sale, no other impairment losses have been recorded through June 30, 2013.
Research and Development	Research and Development Research and development expenses consist of costs incurred to further the Company’s research and development activities and include salaries and related benefits, costs associated with pre-clinical studies and trials, non-clinical activities (such as toxicology studies), regulatory activities, manufacturing activities to support clinical activities, research-related overhead expenses, and fees paid to external service providers that conduct certain research and development, clinical, and manufacturing activities on behalf of the Company. Research and development costs are expensed as incurred.
In-Process Research and Development	In-Process Research and Development In April 2008, the Company acquired certain tangible research and development assets and intellectual property from Pfizer Inc. (Pfizer). As the acquired in-process research and development had not reached technological feasibility and had no alternative future uses in connection with this asset and intellectual property acquisition and the related purchase price allocation, the Company expensed $85,612 as in-process research and development costs in 2008.
Accrued Clinical Development Costs	Accrued Clinical Development Costs Outside research costs are a component of research and development expense. These expenses include fees paid to contract research organizations and other service providers that conduct certain clinical and product development activities on behalf of the Company. Depending upon the timing of payments to the service providers, the Company recognizes prepaid expenses or accrued expenses related to these costs. These accrued or prepaid expenses are based on management’s estimates of the work performed under service agreements, milestones achieved and experience with similar contracts. The Company monitors each of these factors and adjusts estimates accordingly.
Income Taxes	Income Taxes The Company utilizes the liability method of accounting for income taxes as required by ASC 740, Income Taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and the tax basis of assets and liabilities and are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company has incurred operating losses since inception. Accordingly, it is not more likely than not that the Company will realize deferred tax assets and as such, it has recorded a full valuation allowance.
Warrant Liability	Warrant Liability The Company accounts for its warrants issued in connection with its various financing transactions based upon the characteristics and provisions of the instrument. Warrants classified as derivative liabilities are recorded on the Company’s balance sheet at their fair value on the date of issuance and are marked-to-market on each subsequent reporting period, with the fair value changes recognized in the statement of operations. The warrants are measured using the Black-Scholes option-pricing model subsequent to the pricing of the Company’s IPO and a Monte Carlo valuation model for previous periods which are based, in part, upon inputs where there is little or no market data, requiring the Company to develop its own independent assumptions. The Company will continue to adjust the liability for changes in the fair value of these warrants until the earlier of the exercise of the warrants, the expiration of the warrants, or until such time as the warrants are no longer determined to be derivative instruments.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation in accordance with the provisions of ASC 718, Compensation—Stock Compensation. Accordingly, compensation costs related to equity instruments granted are recognized over the requisite service periods of the awards on a straight-line basis at the grant-date fair value calculated using a Black-Scholes option pricing model. Additionally, under the provisions of ASC 718, the Company is required to include an estimate of the number of awards that will be forfeited in calculating compensation costs. Any changes to the estimated forfeiture rates are accounted for prospectively. Stock-based compensation arrangements with non-employees are recognized at the grant-date fair value and then re-measured at each reporting period. Expense is recognized during the period the related services are rendered.

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Measurements

Schedule of the Company's financial assets and liabilities that have been measured at fair value on a recurring basis

Description	Total		Level 1		Level 2		Level 3
June 30, 2013
Assets:
Money market fund	$	16,558,101	$	16,558,101	$	—	$	—
Total assets at fair value	$	16,558,101	$	16,558,101	$	—	$	—
Liabilities:
Warrants	$	2,852,188	$	—	$	—	$	2,852,188
Total liabilities at fair value	$	2,852,188	$	—	$	—	$	2,852,188

December 31, 2012
Assets:
Money market fund	$	6,357,542	$	6,357,542	$	—	$	—
Total assets at fair value	$	6,357,542	$	6,357,542	$	—	$	—
Liabilities:
Warrants	$	265,323	$	—	$	—	$	265,323
Total liabilities at fair value	$	265,323	$	—	$	—	$	265,323

Summary of the changes in the fair value of the Company's Level 3 warrant liabilities

	Warrant Liability
Level 3 Liabilities:
As of December 31, 2012	$	265,323
Change in fair value	2,586,865
As of June 30, 2013	$	2,852,188

Convertible Preferred Stock and Stockholders' Deficit (Tables)

6 Months Ended

Jun. 30, 2013

Convertible Preferred Stock and Stockholders' Deficit

Summary of preferred stock designated as Series A and Series A-1

	June 30, 2013
	Shares Designated	Liquidation Preference Per Share		Shares Issued and Outstanding
Series A	59,538,092	$	1.00	57,598,092
Series A-1	7,862,283	1.16		6,750,000
	67,400,375	$	1.02	64,348,092

	December 31, 2012
	Shares Designated	Liquidation Preference Per Share		Shares Issued and Outstanding
Series A	34,785,000	$	1.00	23,975,000
Series A-1	7,862,283	—		—
	42,647,283	$	1.00	23,975,000

Schedule of the number of common shares which could be issuable upon the conversion of convertible instruments or exercise of options

	June 30, 2013	December 31, 2012
Convertible preferred stock	9,210,999	3,431,865
Warrants for preferred stock	277,690	277,690
Common shares under option	706,040	211,500
Convertible debt	—	3,430,723
Total shares issuable upon conversion or exercise	10,194,729	7,351,778

Stock Compensation (Tables)

6 Months Ended

Jun. 30, 2013

Stock Compensation

Summary of activity relating to the Company's options to purchase common stock

	Number of Options		Weighted-Average Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value

Outstanding at December 31, 2012	211,500		$	1.43	7.5	$	141,389
Granted	545,549		$	3.23
Forfeited or expired	(1,073	)	$	1.54
Exercised	(49,936	)	$	2.47
Outstanding at June 30, 2013	706,040		$	2.74	9.0	$	8,018,165

Summary of information about the stock option plan

The following table summarizes information about the Company’s stock option plan as of June 30, 2013 and December 31, 2012:

	Number of Options	Weighted-Average Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Vested and expected to vest at June 30, 2013	674,040	$	2.73	9.0	$	7,662,092
Exercisable at June 30, 2013	540,126	$	2.15	8.9	$	6,453,501

Debt (Details) - USD ($)			1 Months Ended		6 Months Ended
Debt (Details) - USD ($)	Feb. 12, 2013	Sep. 30, 2012	Feb. 28, 2013	Apr. 30, 2008	Jun. 30, 2013	May 29, 2013	Apr. 19, 2013	Dec. 31, 2012	Nov. 30, 2012	Jan. 30, 2012	Apr. 28, 2008
Series A preferred stock
Debt
Preferred stock, shares issued					57,598,092		17,000,000	23,975,000
Share price of preferred stock (in dollars per share)							$ 1.00
Series A-1 preferred stock
Debt
Preferred stock, shares issued					6,750,000			0
10% Convertible promissory notes \| Series A preferred stock
Debt
Aggregate principal amount			$ 15,700,000
Accrued interest			$ 923,092
Conversion of convertible promissory notes into Series A preferred stock (in shares)	16,623,092		16,623,092	250,000
Conversion price (in dollars per share)			$ 1.00
Short term convertible notes issued January 2012
Debt
Aggregate principal amount										$ 6,000,000
Interest rate (as a percent)										10.00%
Short term convertible notes issued September and November 2012
Debt
Aggregate principal amount									$ 9,700,000
Interest rate (as a percent)									10.00%
Short term convertible notes issued September 2012
Debt
Fair value of beneficial conversion feature		$ 287,990
Short term convertible notes issued September 2012 \| Interest Expense
Debt
Discount on short term convertible notes					$ (229,496)
Pfizer Note
Debt
Aggregate principal amount											$ 5,000,000
Interest rate (as a percent)											8.931%
Outstanding principal amount						$ 7,803,000
Pfizer Note \| Series A-1 preferred stock
Debt
Preferred stock, shares issued						6,750,000
Share price of preferred stock (in dollars per share)						$ 1.1560

Convertible Preferred Stock and Stockholders' Deficit (Details)			1 Months Ended						6 Months Ended		12 Months Ended	59 Months Ended	65 Months Ended
	Apr. 19, 2013 USD ($) $ / shares shares	Feb. 12, 2013 shares	Feb. 28, 2013 shares	Jan. 31, 2011 USD ($) shares	Nov. 30, 2010 USD ($) shares	Apr. 30, 2010 USD ($) shares	Jan. 31, 2010 USD ($) shares	Apr. 30, 2008 USD ($) item shares	Jun. 30, 2013 USD ($) item $ / shares shares	Jun. 30, 2012 USD ($)	Dec. 31, 2012 $ / shares shares	Dec. 31, 2012 USD ($) $ / shares shares	Jun. 30, 2013 USD ($) $ / shares shares	Jul. 02, 2013 $ / shares	Jun. 11, 2013 shares	May 29, 2013 USD ($) $ / shares shares	Apr. 10, 2013 shares	Mar. 25, 2013 shares	Jan. 31, 2013 shares	Sep. 30, 2012 shares	Jan. 23, 2008 shares
Convertible preferred stock and stockholders' deficit
Number of shares of authorized common stock		56,519,253		50,000,000		45,025,145		44,025,145	120,000,000		50,000,000	50,000,000	120,000,000		120,000,000		75,220,375	58,220,375			1,000
Number of new series preferred stock authorized \| item								2
Net proceeds from sale of common stock \| $									$ 123,245	$ 17,362			$ 184,068
Stock issuance costs \| $									$ 1,066,847				$ 1,066,847
Maximum
Convertible Preferred Stock
Percentage of voting power required to be held by the holders of the common stock and preferred stock for determining liquidation preference									50.00%
Warrants for preferred stock
Convertible preferred stock and stockholders' deficit
Share price of preferred stock (in dollars per share) \| $ / shares														$ 6.99
Common shares could be issuable upon conversion of convertible instruments or exercise of options
Convertible Preferred Stock
Total shares issuable upon conversion or exercise									10,194,729		7,351,778
Common shares could be issuable upon conversion of convertible instruments or exercise of options \| Warrants for preferred stock
Convertible Preferred Stock
Total shares issuable upon conversion or exercise									277,690		277,690
Common shares could be issuable upon conversion of convertible instruments or exercise of options \| Common shares under option
Convertible Preferred Stock
Total shares issuable upon conversion or exercise									706,040		211,500
Convertible promissory note \| Common shares could be issuable upon conversion of convertible instruments or exercise of options
Convertible Preferred Stock
Total shares issuable upon conversion or exercise											3,430,723
Pfizer Note
Convertible preferred stock and stockholders' deficit
Aggregate balance \| $																$ 7,803,000
Convertible preferred stock
Convertible preferred stock and stockholders' deficit
Number of shares of authorized preferred stock				41,682,329		40,725,145			67,400,375		42,647,283	42,647,283	67,400,375							42,647,283
Convertible Preferred Stock
Liquidation Preference Per Share (in dollars per share) \| $ / shares									$ 1.02		$ 1.00	$ 1.00	$ 1.02
Shares Issued									64,348,092		23,975,000	23,975,000	64,348,092
Shares Outstanding									64,348,092		23,975,000	23,975,000	64,348,092
Dividends declared, accrued or paid \| $									$ 0			$ 0
Convertible preferred stock \| Minimum
Convertible Preferred Stock
Percentage of preferred stock holders affirmative election required for automatic conversion of temporary equity									60.00%
Convertible preferred stock \| Common shares could be issuable upon conversion of convertible instruments or exercise of options
Convertible Preferred Stock
Total shares issuable upon conversion or exercise									9,210,999		3,431,865
Series A preferred stock
Convertible preferred stock and stockholders' deficit
Number of shares of authorized preferred stock		41,636,970		34,785,000		34,250,000		33,250,000	59,538,092		34,785,000	34,785,000	59,538,092				59,538,092	42,538,092		34,785,000
Number of shares sold	17,000,000			6,700,000	25,000	1,000,000	6,000,000	10,000,000
Share price of preferred stock (in dollars per share) \| $ / shares	$ 1.00
Net proceeds from sale of preferred stock \| $	$ 16,880,463			$ 6,700,000	$ 25,000	$ 1,000,000	$ 6,000,000	$ 10,000,000
Stock issuance costs \| $	$ 119,537
Convertible Preferred Stock
Liquidation Preference Per Share (in dollars per share) \| $ / shares									$ 1.00		$ 1.00	$ 1.00	$ 1.00
Shares Issued	17,000,000								57,598,092		23,975,000	23,975,000	57,598,092
Shares Outstanding									57,598,092		23,975,000	23,975,000	57,598,092
Preferred stock cash dividend rate (as a percent)									8.00%
Original issue price (in dollars per share) \| $ / shares									$ 1.00
Conversion price (in dollars per share) \| $ / shares									$ 6.986				$ 6.986
Conversion rate									0.143				0.143
Series A preferred stock \| Minimum
Convertible Preferred Stock
Percentage of preferred stock holders affirmative election required for automatic conversion of temporary equity									67.00%
Number of times of adjusted original issue price of preferred stock considered for sale of common stock in a firmly under written public offering for determining automatic conversion of temporary equity \| item									3
Gross proceeds from sale of entity's common stock in a firmly underwritten public offering considered for determining automatic conversion of temporary equity \| $									$ 40,000,000
Series A preferred stock \| Convertible promissory note
Convertible preferred stock and stockholders' deficit
Principal amount of the note converted \| $								$ 250,000
Number of shares of preferred stock issued upon conversion of note (in shares)		16,623,092	16,623,092					250,000
Series A-1 preferred stock
Convertible preferred stock and stockholders' deficit
Number of shares of authorized preferred stock						6,475,145		6,475,145	7,862,283		7,862,283	7,862,283	7,862,283						6,897,329	7,862,283
Convertible Preferred Stock
Liquidation Preference Per Share (in dollars per share) \| $ / shares									$ 1.16				$ 1.16
Shares Issued									6,750,000		0	0	6,750,000
Shares Outstanding									6,750,000		0	0	6,750,000
Preferred stock cash dividend rate (as a percent)									8.00%
Original issue price (in dollars per share) \| $ / shares									$ 1.00
Conversion price (in dollars per share) \| $ / shares									$ 6.986				$ 6.986
Conversion rate									0.143				0.143
Series A-1 preferred stock \| Minimum
Convertible Preferred Stock
Gross proceeds from sale of entity's common stock in a firmly underwritten public offering considered for determining automatic conversion of temporary equity \| $									$ 25,000,000
Series A-1 preferred stock \| Pfizer Note
Convertible preferred stock and stockholders' deficit
Share price of preferred stock (in dollars per share) \| $ / shares																$ 1.1560
Convertible Preferred Stock
Shares Issued																6,750,000
Conversion rate									0.124				0.124
Common stock
Convertible preferred stock and stockholders' deficit
Number of shares sold								286,286
Net proceeds from sale of common stock \| $								$ 200

Stock Compensation (Details) - USD ($)		6 Months Ended	12 Months Ended
Stock Compensation (Details) - USD ($)	Jun. 07, 2013	Jun. 30, 2013	Dec. 31, 2012
Number of Options
Outstanding at the beginning of period (in shares)		211,500
Granted (in shares)		545,549
Forfeited or expired (in shares)		(1,073)
Exercised (in shares)		(49,936)
Outstanding at the end of the period (in shares)		706,040	211,500
Weighted-Average Price Per Share
Outstanding at the beginning of period (in dollars per share)		$ 1.43
Granted (in dollars per share)		3.23
Forfeited or expired (in dollars per share)		1.54
Exercised (in dollars per share)		2.47
Outstanding at the end of the period (in dollars per share)		$ 2.74	$ 1.43
Weighted-Average Remaining Contractual Term (Years)
Outstanding at the end of the period		9 years	7 years 6 months
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)		$ 8,018,165	$ 141,389
Information about the stock option plan
Number of Options, vested and expected to vest (in shares)		674,040
Number of Options, exercisable (in shares)		540,126
Weighted-Average Price Per Share, vested and expected to vest (in dollars per share)		$ 2.73
Weighted-Average Price Per Share, exercisable (in dollars per share)		$ 2.15
Weighted-Average Remaining Contractual Term, vested and expected to vest		9 years
Weighted-Average Remaining Contractual Term, exercisable		8 years 10 months 24 days
Aggregate Intrinsic Value, vested and expected to vest (in dollars)		$ 7,662,092
Aggregate Intrinsic Value, exercisable (in dollars)		6,453,501
Additional disclosures
Unrecognized compensation cost (in dollars)		$ 1,100,944
Weighted-average period over which remaining unrecognized compensation cost will be recognized		3 years 1 month 6 days
2008 Incentive Stock Option and Restricted Stock Plan
Stock compensation
Grant period of stock awards		10 years
Vesting percentage on the first anniversary of the option grant		25.00%
Period for which remainder of grant amount will vest on the first day of each calendar quarter		3 years
Expiration period		10 years
Period from cessation of employment within which options expire if not exercised		90 days
Shares reserved		54,129
2013 Stock Option and Incentive Plan
Stock compensation
Initial limit of shares authorized to be sold or issued	1,100,000
Percentage of increase in shares reserved and available for issuance	2.50%

Subsequent Events (Details) - USD ($)	Jul. 11, 2013	Jul. 02, 2013	Jun. 30, 2013	Jun. 11, 2013	Apr. 10, 2013	Mar. 25, 2013	Feb. 12, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Jan. 31, 2011	Apr. 30, 2010	Apr. 30, 2008	Jan. 23, 2008
Subsequent Events
Common stock authorized pursuant to amended and restated certificate of incorporation filed (in shares)			120,000,000	120,000,000	75,220,375	58,220,375	56,519,253	50,000,000				50,000,000	45,025,145	44,025,145	1,000
Cash and cash equivalents			$ 16,626,859					$ 6,511,521		$ 2,049,679	$ 1,571,084
Deferred offering costs			2,449,637
Common stock			396					346
Additional paid-in capital			796,508					609,976
Total stockholders' (deficit) equity			$ (52,338,374)					$ (41,364,703)
Convertible preferred stock
Subsequent Events
Shares Outstanding			64,348,092					23,975,000
Undesignated preferred stock authorized pursuant to amended and restated certificate of incorporation filed (in shares)			67,400,375					42,647,283	42,647,283			41,682,329	40,725,145
Initial Public Offering
Subsequent Events
Cash and cash equivalents			$ 16,626,859
Deferred offering costs			2,449,637
Convertible preferred stock			65,228,086
Common stock			396
Additional paid-in capital			796,508
Total stockholders' (deficit) equity			(52,338,374)
Initial Public Offering \| Pro forma
Subsequent Events
Cash and cash equivalents			91,491,859
Common stock			15,357
Additional paid-in capital			138,424,996
Total stockholders' (deficit) equity			$ 85,305,075
Subsequent event
Subsequent Events
Common stock authorized pursuant to amended and restated certificate of incorporation filed (in shares)		120,000,000
Undesignated preferred stock authorized pursuant to amended and restated certificate of incorporation filed (in shares)		5,000,000
Subsequent event \| Initial Public Offering
Subsequent Events
Common stock sold		5,000,000
Common stock selling price (in dollars per share)		$ 14.00
Net proceeds from the initial public offering		$ 62,700,000
Number of convertible preferred stock converted into common stock (in shares)		9,210,999
Subsequent event \| Initial Public Offering \| Convertible preferred stock
Subsequent Events
Shares Outstanding		64,348,092
Subsequent event \| Underwriter option
Subsequent Events
Common stock sold	750,000
Net proceeds from the initial public offering	$ 9,800,000

Warrants	6 Months Ended
Warrants	Jun. 30, 2013
Warrants
Warrants	4. Warrants In connection with its various financing transactions, the Company issued warrants which are classified as derivative liabilities and recorded on the Company’s balance sheet at their fair value on the date of issuance and are marked-to-market on each subsequent reporting period, with the fair value changes recognized in the statement of operations. On June 30, 2013, the Company estimated the fair values of the warrants at each reporting period using a Black-Scholes option-pricing model, which is based, in part, upon subjective assumptions including but not limited to stock price volatility, the expected life of the warrants, the risk free interest rate and the fair value of the common stock underlying the warrants. The Company estimates the volatility of its stock based on public company peer group historical volatility that is in line with the expected remaining life of the warrants. The risk free interest rate is based on the U.S. Treasury zero-coupon bond for a maturity similar to the expected remaining life of the warrants. The expected remaining life of the warrants is assumed to be equivalent to their remaining contractual term. In prior periods, a Monte Carlo valuation model was utilized to estimate the fair value of the warrants based on the probability and timing of future financings. The Company will continue to adjust the liability for changes in the fair value of these warrants until the earlier of the exercise of the warrants, the expiration of the warrants, or until such time as the warrants are no longer determined to be derivative instruments. As of June 30, 2013, the Company had outstanding warrants to purchase a total of 1,940,000 shares of its Series A preferred stock at an exercise price of $1.00 per share. On July 1, 2013, upon the closing of the IPO, the warrants became exercisable for a total of 277,690 shares of common stock at an exercise price of $6.99 per share. The Company is evaluating the impact of the IPO on the balance sheet classification of the outstanding warrants. The warrants expire in February 2018.

The Company and Basis of Presentation (Details)		6 Months Ended
The Company and Basis of Presentation (Details)	Jun. 11, 2013 $ / shares	Jun. 30, 2013 $ / shares	Dec. 31, 2012 $ / shares
Reverse Stock Split
Reverse stock split ratio of outstanding common stock		0.1431
Par value of common stock (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Initial Public Offering
Reverse Stock Split
Reverse stock split ratio of outstanding common stock	0.1431

Summary of Significant Accounting Policies (Details)	6 Months Ended	12 Months Ended	65 Months Ended
Summary of Significant Accounting Policies (Details)	Jun. 30, 2013 USD ($) item	Dec. 31, 2008 USD ($)	Jun. 30, 2013 USD ($)
Segment Information
Number of operating segments \| item	1
In-Process Research and Development
Acquired in-process research and development		$ 85,612	$ 85,612
Impairment of Long-Lived Assets
Other impairment losses	$ 0
Property and equipment \| Minimum
Property and equipment, net
Estimated useful lives	3 years
Property and equipment \| Maximum
Property and equipment, net
Estimated useful lives	10 years

Warrants (Details) - Series A preferred stock warrant	Jul. 02, 2013 $ / shares shares	Jun. 30, 2013 $ / shares shares
Warrants
Number of shares of common stock to be purchased against outstanding warrants \| shares		1,940,000
Exercise price (in dollars per share) \| $ / shares		1.00
Warrants exercisable into common stock \| shares	277,690
Share price of common stock (in dollars per share) \| $ / shares	$ 6.99

Fair Value Measurements (Details 3) - USD ($)	6 Months Ended	65 Months Ended
Fair Value Measurements (Details 3) - USD ($)	Jun. 30, 2013	Jun. 30, 2013
Nonrecurring fair value measurement
Fair Value Measurements on a Nonrecurring Basis
Impairment loss related to the assets held for sale	$ 27,000	$ 214,393

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2013
Income Taxes
Income Taxes	8. Income Taxes There was no provision for income taxes for the three or six months ended June 30, 2013 and 2012 because the Company has incurred operating losses since inception. At June 30, 2013, the Company has concluded that it is more likely than not that the Company will not realize the benefit of its deferred tax assets due to its history of losses. Accordingly, the net deferred tax assets have been fully reserved.

Fair Value Measurements (Details) - USD ($)	6 Months Ended
Fair Value Measurements (Details) - USD ($)	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Liabilities:
Warrants	$ 2,852,188		$ 265,323
Transfer of assets between levels	0	$ 0
Transfer of liabilities between levels	0	$ 0
Recurring fair value measurement \| Level 1
Assets:
Money market fund	16,558,101		6,357,542
Total assets at fair value	16,558,101		6,357,542
Recurring fair value measurement \| Level 3
Liabilities:
Warrants	2,852,188		265,323
Total liabilities at fair value	2,852,188		265,323
Recurring fair value measurement \| Total
Assets:
Money market fund	16,558,101		6,357,542
Total assets at fair value	16,558,101		6,357,542
Liabilities:
Warrants	2,852,188		265,323
Total liabilities at fair value	$ 2,852,188		$ 265,323

Fair Value Measurements (Details 2) - Warrant Liability	6 Months Ended
Fair Value Measurements (Details 2) - Warrant Liability	Jun. 30, 2013 USD ($)
Changes in the fair value of Level 3 warrant liabilities
Level 3 liabilities beginning balance	$ 265,323
Change in fair value	2,586,865
Level 3 liabilities closing balance	$ 2,852,188

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
Income Taxes (Details) - USD ($)	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Taxes
Provision for income taxes	$ 0	$ 0	$ 0	$ 0

Net Loss Per Common Share (Details)	6 Months Ended	12 Months Ended
Net Loss Per Common Share (Details)	Jun. 30, 2013 shares	Dec. 31, 2012 shares
Net Loss Per Common Share
Total potential dilutive shares	10,219,064	7,351,778
Reverse stock split	0.1431
Convertible preferred stock
Net Loss Per Common Share
Total potential dilutive shares	9,210,999	3,431,865
Warrant
Net Loss Per Common Share
Total potential dilutive shares	277,690	277,690
Common shares under option
Net Loss Per Common Share
Total potential dilutive shares	706,040	211,500
Unvested restricted stock
Net Loss Per Common Share
Total potential dilutive shares	24,335
Convertible debt
Net Loss Per Common Share
Total potential dilutive shares		3,430,723