Esperion Therapeutics (ESPR) 10-Q12 Aug 142014 Q2 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	6 Months Ended
Document and Entity Information (USD $)	Jun. 30, 2014	Aug. 01, 2014
Document and Entity Information	'	'
Entity Registrant Name	'Esperion Therapeutics, Inc.	'
Entity Central Index Key	'0001434868	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	15,445,003
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Entity Listing, Par Value Per Share	$0.00	'

Condensed_Balance_Sheets

Condensed Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:	'	'
Cash and cash equivalents	$47,944	$56,537
Short-term investments	11,780	3,525
Prepaid clinical development costs	1,330	196
Other prepaid and current assets	265	362
Total current assets	61,319	60,620
Property and equipment, net	851	81
Intangible assets	56	56
Long-term investments	7,061	17,537
Total assets	69,287	78,294
Current liabilities:	'	'
Accounts payable	4,211	2,232
Accrued clinical development costs	360	884
Other accrued liabilities	885	1,087
Total current liabilities	5,456	4,203
Long-term debt, net of discount	4,922	'
Total liabilities	10,378	4,203
Commitments and contingencies (Note 5)	'	'
Stockholders' equity:	'	'
Preferred stock, $0.001 par value; 5,000,000 shares authorized as of June 30, 2014 and December 31, 2013; no shares issued or outstanding at June 30, 2014 and December 31, 2013	'	'
Common stock, $0.001 par value; 120,000,000 shares authorized as of June 30, 2014 and December 31, 2013; 15,445,003 shares issued and 15,431,876 outstanding at June 30, 2014 and 15,357,413 shares issued and 15,340,710 outstanding at December 31, 2013	15	15
Additional paid-in capital	144,064	142,142
Accumulated other comprehensive income (loss)	5	-3
Accumulated deficit	-85,175	-68,063
Total stockholders' equity	58,909	74,091
Total liabilities and stockholders' equity	$69,287	$78,294

Condensed_Balance_Sheets_Paren

Condensed Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Preferred stock, par value (in dollars per share)	$0.00	$0.00
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	15,445,003	15,357,413
Common stock, shares outstanding	15,431,876	15,340,710

Condensed_Statements_of_Operat

Condensed Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating expenses:	'	'	'	'
Research and development	$6,528	$3,100	$11,928	$5,193
General and administrative	2,726	1,172	5,216	2,423
Total operating expenses	9,254	4,272	17,144	7,616
Loss from operations	-9,254	-4,272	-17,144	-7,616
Interest expense.	-1	-108	-1	-936
Change in fair value of warrant liability	0	-2,545	0	-2,587
Other income (expense), net	17	4	33	-21
Net loss	-9,238	-6,921	-17,112	-11,160
Net loss per common share (basic and diluted) (in dollars per share)	($0.60)	($19.82)	($1.11)	($32.09)
Weighted-average shares outstanding (basic and diluted)	15,399,018	349,170	15,385,009	347,831
Other comprehensive loss:	'	'	'	'
Unrealized loss on investments	-8	'	-5	'
Total comprehensive loss	($9,246)	($6,921)	($17,117)	($11,160)

Condensed_Statements_of_Cash_F

Condensed Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Operating activities	'	'
Net loss	($17,112)	($11,160)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation expense	53	49
Amortization of debt discount and beneficial conversion feature	'	459
Amortization of debt issuance costs	'	18
Amortization of premiums and discounts on investments	106	'
Revaluation of warrants	0	2,587
Noncash interest expense on convertible notes	'	459
Stock-based compensation expense	1,676	153
Loss related to assets held for sale	29	29
(Gain)/Loss on sale of assets	1	-5
Changes in assets and liabilities:	'	'
Prepaids and other assets	-992	214
Accounts payable	1,789	288
Other accrued liabilities	-732	1,103
Net cash used in operating activities	-15,182	-5,806
Investing activities	'	'
Purchases of investments	-4,800	'
Proceeds from sales/maturities of investments	6,926	'
Proceeds from sale of assets	12	56
Purchase of property and equipment	-638	-18
Net cash provided by investing activities	1,500	38
Financing activities	'	'
Payments for offering costs in connection with initial public offering	'	-1,067
Proceeds from issuance of preferred stock, net of issuance costs	'	16,827
Proceeds from exercise of common stock options	142	123
Proceeds from warrant issuance	78	'
Proceeds from debt issuance, net of issuance costs	4,869	'
Net cash provided by financing activities	5,089	15,883
Net increase (decrease) in cash and cash equivalents	-8,593	10,115
Cash and cash equivalents at beginning of period	56,537	6,512
Cash and cash equivalents at end of period	47,944	16,627
Supplemental disclosure of cash flow information:	'	'
Deferred offering costs not yet paid	'	1,383
Convertible promissory note	'	'
Supplemental disclosure of cash flow information:	'	'
Conversion of promissory notes, including accrued interest into Series A - 1 preferred stock	'	16,623
Pfizer note	'	'
Supplemental disclosure of cash flow information:	'	'
Conversion of promissory notes, including accrued interest into Series A - 1 preferred stock	'	$7,803

Condensed_Statements_of_Cash_F1

Condensed Statements of Cash Flows (Parenthetical) (USD $)	Jun. 30, 2014
In Thousands, unless otherwise specified	Jun. 30, 2014
Convertible promissory note	'
Conversion of convertible promissory notes into preferred stock, accrued interest	$923
Pfizer note	'
Conversion of convertible promissory notes into preferred stock, accrued interest	$274

The_Company_and_Basis_of_Prese

The Company and Basis of Presentation	6 Months Ended
	Jun. 30, 2014
The Company and Basis of Presentation	'
The Company and Basis of Presentation	'
	1. The Company and Basis of Presentation

	The Company is a clinical stage biopharmaceutical company whose planned principal operations are focused on developing and commercializing first in class, oral, low density lipoprotein cholesterol (LDL-cholesterol) lowering therapies for the treatment of patients with hypercholesterolemia and other cardiometabolic risk markers. ETC-1002, the Company’s lead product candidate, is a unique, first in class, orally available, once daily small molecule designed to lower LDL-cholesterol levels and avoid the side effects associated with currently available LDL-cholesterol lowering therapies. ETC-1002 is being developed primarily for patients with hypercholesterolemia and a history of statin intolerance. Phase 2b clinical trials for ETC-1002 are currently underway and build upon the successful and comprehensive Phase 1 and Phase 2a programs. The Company owns the exclusive worldwide rights to ETC-1002 and its other product candidates. Its facilities are located in Ann Arbor and Plymouth, Michigan.

	The Company’s primary activities since incorporation have been conducting research and development activities, including nonclinical and clinical testing, performing business and financial planning, recruiting personnel, and raising capital. Accordingly, the Company has not commenced principal operations and is subject to risks and uncertainties which include 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 interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2013 and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013. The results of operations for the interim periods 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, stockholders’ equity 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.

	Initial Public Offering

	On July 1, 2013, the Company completed its IPO whereby the Company sold 5,000,000 shares of common stock at a price of $14.00 per share. The shares began trading on the Nasdaq Global Market on June 26, 2013. On July 11, 2013, the underwriters exercised their over-allotment option in full and purchased an additional 750,000 shares of common stock at a price of $14.00 per share. The Company received approximately $72.2 million in net proceeds from the IPO, including proceeds from the exercise of the underwriters’ over-allotment option, net of underwriting discounts and commissions and offering expenses. Upon closing of the IPO, all outstanding shares of preferred stock converted into 9,210,999 shares of common stock; and warrants exercisable for convertible preferred stock were automatically converted into warrants exercisable for 277,690 shares of common stock, resulting in the reclassification of the related convertible preferred stock warrant liability of $2.9 million to additional paid-in capital (See Note 4).

	The following table summarizes the Company’s capitalization upon closing of its initial public offering:

	Total common stock issued as of June 30, 2013	396,414
	Conversion of Series A preferred stock into common stock upon closing of IPO	8,244,781
	Conversion of Series A-1 preferred stock into common stock upon closing of IPO	966,218
	Sales of common stock through IPO	5,000,000
	Common stock issued as of July 1, 2013	14,607,413
	Issuance of common stock to underwriters due to exercise of over-allotment	750,000
	Total common stock issued as of July 11, 2013	15,357,413

Summary_of_Significant_Account

Summary of Significant Accounting Policies	6 Months Ended
Summary of Significant Accounting Policies	Jun. 30, 2014
Summary of Significant Accounting Policies	'
Summary of Significant Accounting Policies	'
	2. Summary of Significant Accounting Policies

	Recent Accounting Pronouncements

	In June 2014, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2014-10 which improves financial reporting by reducing the cost and complexity associated with the incremental reporting requirements for development stage entities without reducing the relevance of information provided to users of financial statements. Under the amended guidance, issuers are no longer required to (1) present inception-to-date information in the statements of income, cash flows, and shareholder equity, (2) label the financial statements as those of a development stage entity, (3) disclose a description of the development stage activities in which the entity is engaged, and (4) disclose in the first year in which the entity is no longer a development stage entity that in prior years it had been in the development stage. The Company adopted the amendment which resulted in a reduction in disclosures previously relating to a development stage entity.

	There have been no other material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013.

Debt

Debt	6 Months Ended
	Jun. 30, 2014
Debt	'
Debt	'
	3. Debt

	Credit Facility

	In June 2014, the Company entered into a loan and security agreement (the “Credit Facility”) with Oxford Finance LLC which provides for initial borrowings of $5.0 million under term loans (“Term A Loan”) and additional borrowings of $15.0 million (“Term B Loan”) at the Company’s option, for a maximum of $20.0 million. On June 30, 2014, the Company received proceeds of $5.0 million from the issuance of secured promissory notes under the Term A Loan. The remaining $15.0 million available under Term B Loan becomes available to be drawn down, at the Company’s sole discretion, until March 31, 2015, upon achieving positive development results in either of the Company’s ongoing Phase 2b clinical studies (a “Milestone Event”). All secured promissory notes issued under the Credit Facility are due on July 1, 2018 and are collateralized by substantially all of the Company’s personal property, other than its intellectual property.

	The Company is obligated to make monthly, interest-only payments on Term A Loan until July 1, 2015 and, thereafter, to pay 36 months consecutive, equal monthly installments of principal and interest from August 1, 2015 through July 1, 2018. Upon a Milestone Event, and the subsequent borrowing under the Term B Loan, the term of monthly, interest-only payments will be extended until January 1, 2016. Term A Loan bears interest at an annual rate of 6.40%. In the event the Company enters into Term B Loan, the interest rate will be the greater of (i) 6.40% or (ii) three month LIBOR rate three business days prior to the funding of the new term loan plus an additional 6.17%. In addition, a final payment equal to 8.0% of any amounts drawn under the Credit Facility is due upon the earlier of the maturity date or prepayment of the term loans. The Company is recognizing the final payment as interest expense using the effective interest method over the life of the Credit Facility.

	There are no financial covenants associated to the Credit Facility. However, there are negative covenants that limit or restrict the Company’s activities, which include limitations on incurring indebtedness, granting liens, mergers or acquisitions, dispositions of assets, making certain investments, entering into certain transactions with affiliates, paying dividends or distributions, encumbering or pledging interest in its intellectual property and certain other business transactions. Additionally, the Credit Facility also includes events of default, the occurrence and continuation of any of which provides the lenders the right to exercise remedies against the Company and the collateral securing the loans under the Credit Facility, which includes cash. These events of default include, among other things, non-payment of any amounts due under the Credit Facility, insolvency, the occurrence of a material adverse event, inaccuracy of representations and warranties, cross default to material indebtedness and a material judgment against the Company. Upon the occurrence of an event of default, all obligations under the Credit Facility shall accrue interest at a rate equal to the fixed annual rate plus five percentage points.

	In connection with the borrowing of Term A Loan, the Company issued a warrant (the “Warrant”) to purchase 8,230 shares of common stock at an exercise price of $15.19 (see Note 4). The Warrant resulted in a debt discount of $0.1 million which is amortized into interest expense using the effective interest method over the life of Term A Loan. In addition, deferred financing costs of $0.1 million included in other prepaid and current assets on the consolidated balance sheet as of June 30, 2014 are amortized to interest expense using the effective-interest method over the same term. As of June 30, 2014, the remaining unamortized discount and debt issuance costs associated with the debt were $0.1 million and $0.1 million, respectively.

	Estimated future principal payments due under the Credit Facility are as follows:

	Years Ending December 31,	(in thousands)
	2014	$	—
	2015	638
	2016	1,604
	2017	1,709
	2018	1,049
	Total	$	5,000

	During the six months ended June 30, 2014, the Company recognized $1,000 of interest expense related to the Credit Facility.

	Convertible Notes

	In January 2012, the Company issued $6.0 million of 10% convertible promissory notes to certain existing investors for cash. In September and November 2012, the Company issued the aggregate of $9.7 million of 10% convertible promissory notes that mature on September 4, 2013 for cash to certain existing investors. In connection with the September convertible note financing, the Company and the holders of the January 2012 convertible promissory notes agreed to extend the maturity date of the January 2012 notes to September 4, 2013. In February 2013, these convertible promissory notes, with an outstanding principal of $15.7 million and accrued interest of $0.9 million, were amended and then converted into 16,623,092 shares of Series A preferred stock, in accordance with their terms and at their conversion price of $1.00 per share, and following such conversion, the notes were cancelled.

	The holders of the September convertible promissory notes received the benefit of a deemed conversion price of the September convertible promissory notes that were below the estimated fair value of the Series A convertible preferred stock at the time of their issuance. The fair value of this beneficial conversion feature was estimated to be $0.3 million. The fair value of this beneficial conversion feature was recorded to debt discount and amortized to interest expense using the effective interest method over the term of the convertible promissory notes. As a result of the conversion of the convertible promissory notes into shares of Series A preferred stock in February 2013, the Company recorded an accretion of the beneficial conversion feature of $0 and $0.2 million as interest expense during the six months ended June 30, 2014 and 2013, respectively.

	In connection with the issuance of the September and the November 2012 convertible promissory notes, the Company issued warrants to purchase shares of Series A preferred stock for an aggregate price of $9,700. The estimated fair value of the warrants at issuance was $0.3 million. The proceeds from the sale of the preferred stock and warrants were allocated with $9.4 million to the convertible promissory notes and $0.3 million to warrants. This resulted in a discount on the convertible promissory notes which was amortized into interest expense, using the effective interest method, over the life of the convertible promissory notes (see Note 4). As a result of the conversion of the convertible promissory notes into shares of Series A preferred stock in February 2013, the Company recorded $0 and $0.2 million of interest expense for the accretion of this discount during the six months ended June 30, 2014 and 2013, respectively.

	In April 2008, the Company acquired all of the capital stock of Esperion from Pfizer in exchange for a non-subordinated convertible note in the original principal amount of $5.0 million. This convertible promissory note had a maturity date of April 28, 2018. The note bore interest at 8.931% annually, payable semiannually on June 30 and December 31 by adding such unpaid interest to the principal of the note, which would thereafter accrue interest.

	In May 2013 the Company entered into a stock purchase agreement with Pfizer Inc. and sold 6,750,000 shares of Series A-1 preferred stock at a price of $1.1560 per share, which was the fair value at the transaction date. The purchase price was paid through the cancellation of all outstanding indebtedness, including accrued interest, under the Pfizer convertible promissory note, which had an outstanding balance, including accrued interest, of $7.8 million as of May 29, 2013. The Series A-1 preferred stock issued in connection with this transaction was subsequently converted into 966,218 shares of common stock upon completion of the IPO on July 1, 2013.

Warrants

Warrants	6 Months Ended
Warrants	Jun. 30, 2014
Warrants	'
Warrants	'
	4. Warrants

	In connection with the Credit Facility entered into in June 2014, the Company issued a warrant to purchase 8,230 shares of common stock at an exercise price of $15.19. The Warrant will terminate on the earlier of June 30, 2019 and the closing of a merger or consolidation transaction in which the Company is not the surviving entity. The warrants were recorded at fair value of $0.1 million to additional-paid-in-capital in accordance with ASC 815-10 based upon the allocation of the debt proceeds. The Company estimated the fair value of the warrants 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 connection with its various convertible note financing transactions, the Company issued warrants to purchase shares of preferred stock which had provisions where the underlying issuance was contingently redeemable based on events outside the Company’s control and were recorded as a liability in accordance with ASC 480-10. The warrants were classified as liabilities and were recorded on the Company’s balance sheet at fair value on the date of issuance and marked- to-market on each subsequent reporting period, with the fair value changes recognized in the statement of operations. Subsequent to the pricing of the IPO, 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. Prior to the pricing of the IPO, 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 assumptions used in calculating the estimated fair market value at each reporting period prior to the closing of the Company’s IPO represented the Company’s best estimate, however, do involve inherent uncertainties. The estimated fair value of the warrants was determined using the Monte Carlo valuation model which totaled $0.3 million and was comprised of $0.1 million and $0.2 million as of and for the September and November 2012 financing, respectively, and was recorded as a discount on the related convertible promissory notes and amortized as interest expense over the term of the convertible promissory notes. Inherent in the Monte Carlo valuation model are assumptions related to expected stock-price volatility, expected life and risk-free interest rate. 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 on the grant date for a maturity similar to the expected remaining life of the warrants. The expected life of the warrants is assumed to be equivalent to their remaining contractual term. The dividend rate is based on the historical rate, which the Company anticipates to remain at zero. The Monte Carlo model was used prior to the closing of the Company’s IPO to appropriately value the potential future exercise price based on various exit scenarios. This requires Level 3 inputs which are based on the Company’s estimates of the probability and timing of potential future financings.

	Upon the closing of the Company’s IPO, all warrants exercisable for 1,940,000 shares of Series A preferred stock, at an exercise price of $1.00 per share, were automatically converted into warrants exercisable for 277,690 shares of common stock, at an exercise price of $6.99 per share. As a result, the Company concluded the warrants outstanding no longer met the criteria to be classified as liabilities and were reclassified to additional paid-in capital at fair value on the date of reclassification. The 277,690 warrants outstanding as of June 30, 2014 expire in February 2018. During the three and six months ended June 30, 2014 and 2013, the Company recognized a loss of $0, $0, $2.5 million and $2.6 million, respectively, relating to the change in the fair value of the warrant liability.

	As of June 30, 2014, the Company had warrants outstanding that were exercisable for a total of 285,920 shares of common stock at a weighted-average exercise price of $7.23 per share.

Commitments_and_contingencies

Commitments and contingencies	6 Months Ended
	Jun. 30, 2014
Commitments and contingencies	'
Commitments and contingencies	'
	5. Commitments and contingencies

	In February 2014, the Company entered into an operating lease agreement for its principal executive offices located in Ann Arbor, Michigan commencing in April 2014 with a term of 63 months. The Company’s lease provides for fixed monthly rent for the term of the lease, with monthly rent increasing every 12 months subsequent to the first three months of the lease, and also provides for certain rent adjustments to be paid as determined by the landlord.

	In May 2014, the Company entered into the third amendment to the operating lease agreement for its laboratory facility in Plymouth, Michigan. The amendment provides in part that (i) the expiration date of the term of the lease is extended from April 2014 to April 2017, (ii) the rentable laboratory space is adjusted to 3,045 square feet, (iii) the Company’s proportionate share of the landlord’s expenses and taxes is adjusted to 7.40%, (iv) the Company may exercise its option to renew the lease for one term of three years through written notice to the landlord by February 2017 and (v) the annual base rent under the lease is decreased to $37,000, subject to increase and adjustments provided in the lease.

	The following table summarizes the Company’s future minimum lease payments as of June 30, 2014:

		Total		Less than		1-3 Years		3-5 Years		More than
				1 Year						5 Years
		(in thousands)
	Operating leases	$	615	$	128	$	267	$	211	$	9
	Total	$	615	$	128	$	267	$	211	$	9

Investments

Investments	6 Months Ended
	Jun. 30, 2014
Investments	'
Investments	'
	6. Investments

	The following table summarizes the Company’s cash equivalents and investments:

		June 30, 2014
		Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
		(in thousands)
	Cash equivalents:
	Money market funds	$	357	$	—	$	—		$	357
	Short-term investments:
	Certificates of deposit	237		—		—			237
	U.S. treasury notes	9,101		5		—			9,106
	U.S. government agency securities	2,437		—		—			2,437
	Long-term investments:
	U.S. treasury notes	1,998		4		—			2,002
	U.S. government agency securities	5,063		—		(4		)	5,059
	Total	$	19,193	$	9	$	(4	)	$	19,198

		December 31, 2013
		Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
		(in thousands)
	Cash equivalents:
	Money market funds	$	5,356	$	—	$	—		$	5,356
	Short-term investments:
	U.S. treasury notes	2,071		—		—			2,071
	U.S. government agency securities	1,454		—		—			1,454
	Long-term investments:
	Certificates of deposit	238		—		—			238
	U.S. treasury notes	9,116		3		(2		)	9,117
	U.S. government agency securities	8,187		1		(5		)	8,183
	Total	$	26,422	$	4	$	(7	)	$	26,419

	At June 30, 2014 and December 31, 2013, remaining contractual maturities of available for sale investments classified as current on the balance sheet were less than 12 months, and remaining contractual maturities of available for sale investments classified as long term were less than two years.

	There were no unrealized gains or losses on investments reclassified from accumulated other comprehensive income (loss) to other income (expense) in the Statement of Operations during the six months ended June 30, 2014 and 2013.

Fair_Value_Measurements

Fair Value Measurements	6 Months Ended
Fair Value Measurements	Jun. 30, 2014
Fair Value Measurements	'
Fair Value Measurements	'
	7. 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
		(in thousands)
	June 30, 2014
	Assets:
	Money market funds	$	357	$	357	$	—	$	—
	Available for sale securities:
	Certificates of deposit	237		237		—		—
	U.S. treasury notes	11,108		11,108		—		—
	U.S. government agency securities	7,496		—		7,496		—
	Total assets at fair value	$	19,198	$	11,702	$	7,496	$	—
	December 31, 2013
	Assets:
	Money market funds	$	5,356	$	5,356	$	—	$	—
	Available for sale securities:
	Certificates of deposit	238		238		—		—
	U.S. treasury notes	11,188		11,188		—		—
	U.S. government agency securities	9,637		—		9,637		—
	Total assets at fair value	$	26,419	$	16,782	$	9,637	$	—

	There were no transfers between Levels 1, 2 or 3 during the six months ended June 30, 2014 and 2013.

	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, 2014 and 2013, the Company recognized impairment expense of $0 and $27,000, respectively, related to the assets held for sale. 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.

Convertible_Preferred_Stock_an

Convertible Preferred Stock and Stockholders' Equity	6 Months Ended
Convertible Preferred Stock and Stockholders' Equity	Jun. 30, 2014
Convertible Preferred Stock and Stockholders' Equity	'
Convertible Preferred Stock and Stockholders' Equity	'
	8. Convertible Preferred Stock and Stockholders’ Equity

	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 per share for proceeds of $16.9 million, which is net of issuance costs of $0.1 million, 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 $7.8 million as of May 29, 2013. Each share of Series A-1 preferred stock issued in the agreement was convertible into 0.143 shares of common stock upon the closing of the Company’s IPO.

	Upon the closing of the Company’s IPO on July 1, 2013, all of the outstanding shares of convertible preferred stock were converted into 9,210,999 shares of common stock. As of June 30, 2014, the Company did not have any convertible preferred stock issued or outstanding.

Stock_Compensation

Stock Compensation	6 Months Ended
	Jun. 30, 2014
Stock Compensation	'
Stock Compensation	'
	9. Stock Compensation

	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 Company’s 2008 Incentive Stock Option and Restricted Stock Plan (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. On January 1, 2014, the number of shares of stock reserved and available for issuance under the 2013 Plan increased by 383,935 shares.

	Under the 2013 Plan the vesting of options granted or restricted awards given will be determined individually with each option grant. 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.

	The following table summarizes the activity relating to the Company’s options to purchase common stock for the six months ended June 30, 2014:

		Number of		Weighted-Average		Weighted-Average	Aggregate
		Options		Price		Remaining	Intrinsic
				Per Share		Contractual	Value
						Term (Years)
							(in thousands)
	Outstanding at December 31, 2013	1,401,101		$	9.59	8.95	$	7,755
	Granted	251,500		$	14.67
	Forfeited or expired (vested and unvested)	(38,771	)	$	6.17
	Exercised	(87,590	)	$	1.62
	Outstanding at June 30, 2014	1,526,240		$	10.98	8.69	$	8,150

	The following table summarizes information about the Company’s stock option plan as of June 30, 2014:

		Number of		Weighted-Average		Weighted-Average	Aggregate
		Options		Price		Remaining	Intrinsic
				Per Share		Contractual	Value
						Term (Years)
							(in thousands)
	Vested and expected to vest at June 30, 2014	1,465,510		$	10.9	8.67	$	7,928
	Exercisable at June 30, 2014	609,994		$	4.59	7.78	$	6,956

	As of June 30, 2014, there was approximately $8.4 million of unrecognized compensation cost related to unvested options, adjusted for forfeitures, which will be recognized over a weighted-average period of approximately 3 years.

Income_Taxes

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2014
Income Taxes	'
Income Taxes	'
	10. Income Taxes

	There was no provision for income taxes for the three or six months ended June 30, 2014 and 2013 because the Company has incurred operating losses since inception. At June 30, 2014, 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.

Net_Loss_Per_Common_Share

Net Loss Per Common Share	6 Months Ended
	Jun. 30, 2014
Net Loss Per Common Share	'
Net Loss Per Common Share	'
	11. Net Loss Per Common Share

	Basic net loss per share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, warrants for common stock, stock options and unvested restricted stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. Interest expense for convertible debt that is dilutive is added back to net income in the calculation of diluted net loss per share.

	The shares outstanding at the end of the respective periods presented below, after giving effect for the 1-for-6.986 reverse stock split, were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect:

		June 30,	December 31,
		2014	2013

	Warrants for common stock	285,920	277,690
	Common shares under option	1,526,240	1,401,101
	Unvested restricted stock	13,127	16,703
	Total potential dilutive shares	1,825,287	1,695,494

The_Company_and_Basis_of_Prese1

The Company and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2014
The Company and Basis of Presentation	'
Basis of Presentation	'
	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 interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2013 and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013. The results of operations for the interim periods 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	'
	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, stockholders’ equity 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.
Initial Public Offering	'
	Initial Public Offering

	On July 1, 2013, the Company completed its IPO whereby the Company sold 5,000,000 shares of common stock at a price of $14.00 per share. The shares began trading on the Nasdaq Global Market on June 26, 2013. On July 11, 2013, the underwriters exercised their over-allotment option in full and purchased an additional 750,000 shares of common stock at a price of $14.00 per share. The Company received approximately $72.2 million in net proceeds from the IPO, including proceeds from the exercise of the underwriters’ over-allotment option, net of underwriting discounts and commissions and offering expenses. Upon closing of the IPO, all outstanding shares of preferred stock converted into 9,210,999 shares of common stock; and warrants exercisable for convertible preferred stock were automatically converted into warrants exercisable for 277,690 shares of common stock, resulting in the reclassification of the related convertible preferred stock warrant liability of $2.9 million to additional paid-in capital (See Note 4).

	The following table summarizes the Company’s capitalization upon closing of its initial public offering:

	Total common stock issued as of June 30, 2013	396,414
	Conversion of Series A preferred stock into common stock upon closing of IPO	8,244,781
	Conversion of Series A-1 preferred stock into common stock upon closing of IPO	966,218
	Sales of common stock through IPO	5,000,000
	Common stock issued as of July 1, 2013	14,607,413
	Issuance of common stock to underwriters due to exercise of over-allotment	750,000
	Total common stock issued as of July 11, 2013	15,357,413

Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements

	In June 2014, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2014-10 which improves financial reporting by reducing the cost and complexity associated with the incremental reporting requirements for development stage entities without reducing the relevance of information provided to users of financial statements. Under the amended guidance, issuers are no longer required to (1) present inception-to-date information in the statements of income, cash flows, and shareholder equity, (2) label the financial statements as those of a development stage entity, (3) disclose a description of the development stage activities in which the entity is engaged, and (4) disclose in the first year in which the entity is no longer a development stage entity that in prior years it had been in the development stage. The Company adopted the amendment which resulted in a reduction in disclosures previously relating to a development stage entity.

	There have been no other material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013.

The_Company_and_Basis_of_Prese2

The Company and Basis of Presentation (Tables)	6 Months Ended
The Company and Basis of Presentation (Tables)	Jun. 30, 2014
The Company and Basis of Presentation	'
Summary of the Company's capitalization upon closing of its initial public offering	'


	Total common stock issued as of June 30, 2013	396,414
	Conversion of Series A preferred stock into common stock upon closing of IPO	8,244,781
	Conversion of Series A-1 preferred stock into common stock upon closing of IPO	966,218
	Sales of common stock through IPO	5,000,000
	Common stock issued as of July 1, 2013	14,607,413
	Issuance of common stock to underwriters due to exercise of over-allotment	750,000
	Total common stock issued as of July 11, 2013	15,357,413

Debt_Tables

Debt (Tables)	6 Months Ended
	Jun. 30, 2014
Debt	'
Schedule of estimated future principal payments due	'


	Years Ending December 31,	(in thousands)
	2014	$	—
	2015	638
	2016	1,604
	2017	1,709
	2018	1,049
	Total	$	5,000

Commitments_and_contingencies_

Commitments and contingencies (Tables)	6 Months Ended
	Jun. 30, 2014
Commitments and contingencies	'
Summary of future minimum lease payments	'
	The following table summarizes the Company’s future minimum lease payments as of June 30, 2014:

		Total		Less than		1-3 Years		3-5 Years		More than
				1 Year						5 Years
		(in thousands)
	Operating leases	$	615	$	128	$	267	$	211	$	9
	Total	$	615	$	128	$	267	$	211	$	9

Investments_Tables

Investments (Tables)	6 Months Ended
	Jun. 30, 2014
Investments	'
Summary of the Company's cash equivalents and investments	'


		June 30, 2014
		Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
		(in thousands)
	Cash equivalents:
	Money market funds	$	357	$	—	$	—		$	357
	Short-term investments:
	Certificates of deposit	237		—		—			237
	U.S. treasury notes	9,101		5		—			9,106
	U.S. government agency securities	2,437		—		—			2,437
	Long-term investments:
	U.S. treasury notes	1,998		4		—			2,002
	U.S. government agency securities	5,063		—		(4		)	5,059
	Total	$	19,193	$	9	$	(4	)	$	19,198

		December 31, 2013
		Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
		(in thousands)
	Cash equivalents:
	Money market funds	$	5,356	$	—	$	—		$	5,356
	Short-term investments:
	U.S. treasury notes	2,071		—		—			2,071
	U.S. government agency securities	1,454		—		—			1,454
	Long-term investments:
	Certificates of deposit	238		—		—			238
	U.S. treasury notes	9,116		3		(2		)	9,117
	U.S. government agency securities	8,187		1		(5		)	8,183
	Total	$	26,422	$	4	$	(7	)	$	26,419

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2014
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
		(in thousands)
	June 30, 2014
	Assets:
	Money market funds	$	357	$	357	$	—	$	—
	Available for sale securities:
	Certificates of deposit	237		237		—		—
	U.S. treasury notes	11,108		11,108		—		—
	U.S. government agency securities	7,496		—		7,496		—
	Total assets at fair value	$	19,198	$	11,702	$	7,496	$	—
	December 31, 2013
	Assets:
	Money market funds	$	5,356	$	5,356	$	—	$	—
	Available for sale securities:
	Certificates of deposit	238		238		—		—
	U.S. treasury notes	11,188		11,188		—		—
	U.S. government agency securities	9,637		—		9,637		—
	Total assets at fair value	$	26,419	$	16,782	$	9,637	$	—

Stock_Compensation_Tables

Stock Compensation (Tables)	6 Months Ended
Stock Compensation (Tables)	Jun. 30, 2014
Stock Compensation	'
Summary of activity relating to the Company's options to purchase common stock	'


		Number of		Weighted-Average		Weighted-Average	Aggregate
		Options		Price		Remaining	Intrinsic
				Per Share		Contractual	Value
						Term (Years)
							(in thousands)
	Outstanding at December 31, 2013	1,401,101		$	9.59	8.95	$	7,755
	Granted	251,500		$	14.67
	Forfeited or expired (vested and unvested)	(38,771	)	$	6.17
	Exercised	(87,590	)	$	1.62
	Outstanding at June 30, 2014	1,526,240		$	10.98	8.69	$	8,150
Summary of information about the stock option plan	'


		Number of		Weighted-Average		Weighted-Average	Aggregate
		Options		Price		Remaining	Intrinsic
				Per Share		Contractual	Value
						Term (Years)
							(in thousands)
	Vested and expected to vest at June 30, 2014	1,465,510		$	10.9	8.67	$	7,928
	Exercisable at June 30, 2014	609,994		$	4.59	7.78	$	6,956

Net_Loss_Per_Common_Share_Tabl

Net Loss Per Common Share (Tables)	6 Months Ended
Net Loss Per Common Share (Tables)	Jun. 30, 2014
Net Loss Per Common Share	'
Schedule of anti-dilutive securities excluded from the calculation of diluted net loss per share	'


		June 30,	December 31,
		2014	2013

	Warrants for common stock	285,920	277,690
	Common shares under option	1,526,240	1,401,101
	Unvested restricted stock	13,127	16,703
	Total potential dilutive shares	1,825,287	1,695,494

The_Company_and_Basis_of_Prese3

The Company and Basis of Presentation (Details) (USD $)

0 Months Ended

In Millions, except Share data, unless otherwise specified

Jun. 11, 2013

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Jul. 02, 2013

Jul. 11, 2013

Jul. 02, 2013

Jun. 11, 2013

Jul. 02, 2013

Jul. 11, 2013

Common stock

Initial Public Offering

Over-allotment option

Warrant

Common stock

Convertible preferred stock

Additional paid-in capital

Warrant liabilities

Reverse Stock Split

Reverse stock split ratio of outstanding common stock

0.1431

Par value of common stock (in dollars per share)

$0.00

Initial Public Offering

Original issue price (in dollars per share)

$14

Net proceeds from the IPO, including proceeds from the exercise of the underwriters' over-allotment option

$72.20

Number of shares of convertible preferred stock converted into common stock

9,210,999

Warrants exercisable into common stock (in shares)

8,230

277,690

Reclassification of convertible preferred stock warrant liability to additional paid-in capital

$2.90

($2.90)

The_Company_and_Basis_of_Prese4

The Company and Basis of Presentation (Details 2)	Jun. 30, 2014	Dec. 31, 2013	Jul. 11, 2013	Jul. 02, 2013	Jun. 30, 2013	Jul. 02, 2013	Jul. 02, 2013	Jul. 02, 2013	Jul. 11, 2013
						Initial Public Offering	Initial Public Offering	Initial Public Offering	Over-allotment option
						Series A preferred stock	Series A-1 preferred stock	Common stock
Movement in Company's capitalization upon closing of initial public offering	'	'	'	'	'	'	'	'	'
Balance (in shares)	15,445,003	15,357,413	15,357,413	14,607,413	396,414	'	'	'	'
Conversion of preferred stock into common stock upon closing of IPO (in shares)	'	'	'	'	'	8,244,781	966,218	9,210,999	'
Common stock sold (in shares)	'	'	'	'	'	'	'	5,000,000	750,000
Balance (in shares)	15,445,003	15,357,413	15,357,413	14,607,413	396,414	'	'	'	'

Debt_Details

Debt (Details) (USD $)

6 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

6 Months Ended

0 Months Ended

6 Months Ended

1 Months Ended

6 Months Ended

Jun. 30, 2014

Apr. 19, 2013

Jun. 30, 2014

Jul. 02, 2013

Feb. 28, 2013

Jan. 31, 2012

Nov. 30, 2012

Feb. 28, 2013

Jun. 30, 2014

Jun. 30, 2013

Sep. 30, 2012

29-May-13

Apr. 28, 2008

Jul. 02, 2013

29-May-13

Jun. 30, 2014

Series A preferred stock

Warrant

Series A preferred stock warrant

10% Convertible promissory notes

Short term convertible notes issued January 2012

Short term convertible notes issued September and November 2012

Short term convertible notes issued September 2012

Pfizer Note

Credit Facility

Term A Loan

Term B Loan

Series A preferred stock

Warrant

Series A preferred stock warrant

Interest Expense

Warrant

Series A-1 preferred stock

item

Warrant

Secured promissory notes

Estimated fair value

Series A preferred stock

Estimated fair value

Debt

Maximum borrowing capacity

$20,000,000

$5,000,000

$15,000,000

Proceeds from issuance of debt

5,000,000

Remaining borrowing capacity

15,000,000

Period of consecutive equal monthly installments of principal and interest

'36 months

Interest rate (as a percent)

10.00%

8.93%

6.40%

Reference rate

'three month LIBOR

Number of business days prior to funding of new term loan

'3 days

Interest rate margin (as a percent)

6.17%

Percentage of final payment equal to amount drawn under the Credit Facility

8.00%

Number of financial covenants associated to the Credit Facility

Warrants exercisable into stock (in shares)

1,940,000

8,230

Exercise price (in dollars per share)

$7.23

$15.19

Unamortized discount

100,000

Deferred financing costs

100,000

Estimated future principal payments due under the Credit Facility

2015

638,000

2016

1,604,000

2017

1,709,000

2018

1,049,000

Total

5,000,000

Interest expense

1,000

Aggregate principal amount

15,700,000

6,000,000

9,700,000

5,000,000

Net proceeds from issuance of debt

4,869,000

100,000

Estimated fair value of warrants

300,000

100,000

Accrued interest

900,000

Conversion of convertible promissory notes into Series A preferred stock (in shares)

16,623,092

Conversion price (in dollars per share)

Outstanding principal amount

7,800,000

Fair value of beneficial conversion feature

300,000

Amortization of debt discount and beneficial conversion

200,000

Aggregate purchase price of warrants

9,700

Short term borrowings with related parties, net of debt discount

$9,400,000

Preferred stock, shares issued

6,750,000

Share price of preferred stock (in dollars per share)

$1.16

Number of shares of preferred stock converted into shares of common stock

966,218

Warrants_Details

Warrants (Details) (USD $)

3 Months Ended

6 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Mar. 31, 2014

Nov. 30, 2012

Sep. 30, 2012

Nov. 30, 2012

Jul. 02, 2013

Nov. 30, 2012

Jun. 30, 2014

Jul. 02, 2013

Warrant

Series A preferred stock warrant

Common stock

Estimated fair value

Warrant

Short term convertible notes issued September and November 2012

Short term convertible notes issued September 2012

Short term convertible notes issued November 2012

Short term convertible notes issued September and November 2012

Warrants

Warrants exercisable into stock (in shares)

1,940,000

8,230

277,690

Exercise price (in dollars per share)

$7.23

$15.19

Fair value of warrants

$100,000

Estimated fair value

300,000

100,000

200,000

300,000

Share price of common stock (in dollars per share)

$6.99

Number of shares of common stock to be purchased against outstanding warrants

285,920

277,690

Loss related to the change in the fair value of the warrant liability

$2,545,000

$2,587,000

Commitments_and_contingencies_1

Commitments and contingencies (Details) (USD $)	1 Months Ended	6 Months Ended	1 Months Ended
	Feb. 28, 2014	Jun. 30, 2014	31-May-14
			Third amendment to the operating lease agreement for laboratory facility in Plymouth, Michigan
			sqft
			item
Commitments and contingencies	'	'	'
Term period of lease	'63 months	'	'
Operating lease period for monthly rent increasing in fixed monthly rent	'	'12 months	'
Operating lease period after which monthly rent increase	'	'3 months	'
Commitments and contingencies	'	'	'
Adjusted rentable laboratory space (in square feet)	'	'	3,045
Adjusted proportionate share of landlord's expenses and taxes (as a percent)	'	'	7.40%
Number of terms which Company may exercise to renew lease	'	'	1
Lease renewal term	'	'	'3 years
Annual base rent under new lease agreement	'	'	$37,000
Operating leases	'	'	'
Total	'	615,000	'
Less than 1 Year	'	128,000	'
1-3 Years	'	267,000	'
3-5 Years	'	211,000	'
More than 5 Years	'	9,000	'
Total	'	'	'
Total	'	615,000	'
Less than 1 Year	'	128,000	'
1-3 Years	'	267,000	'
3-5 Years	'	211,000	'
More than 5 Years	'	$9,000	'

Investments_Details

Investments (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Cash equivalents and investments	'	'	'	'	'
Gross Unrealized Gains	$9	'	$9	'	$4
Gross Unrealized Losses	-4	'	-4	'	-7
Total, Amortized Cost	19,193	'	19,193	'	26,422
Total, Estimated Fair Value	19,198	'	19,198	'	26,419
Other income (expense), net	17	4	33	-21	'
Reclassification out of accumulated other comprehensive income (loss)	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Other income (expense), net	'	'	0	0	'
Short-term investments \| U.S. treasury notes	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Investments, Amortized Cost	9,101	'	9,101	'	2,071
Gross Unrealized Gains	5	'	5	'	'
Investments, Estimated Fair Value	9,106	'	9,106	'	2,071
Short-term investments \| U.S. government agency securities	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Investments, Amortized Cost	2,437	'	2,437	'	1,454
Investments, Estimated Fair Value	2,437	'	2,437	'	1,454
Long-term investments \| U.S. treasury notes	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Investments, Amortized Cost	1,998	'	1,998	'	9,116
Gross Unrealized Gains	4	'	4	'	3
Gross Unrealized Losses	'	'	'	'	-2
Investments, Estimated Fair Value	2,002	'	2,002	'	9,117
Long-term investments \| U.S. government agency securities	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Investments, Amortized Cost	5,063	'	5,063	'	8,187
Gross Unrealized Gains	'	'	'	'	1
Gross Unrealized Losses	-4	'	-4	'	-5
Investments, Estimated Fair Value	5,059	'	5,059	'	8,183
Money market funds	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Cash equivalents, Estimated Fair Value	357	'	357	'	5,356
Investments, Amortized Cost	357	'	357	'	5,356
Certificates of deposit \| Short-term investments	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Investments, Amortized Cost	237	'	237	'	'
Investments, Estimated Fair Value	237	'	237	'	'
Certificates of deposit \| Long-term investments	'	'	'	'	'
Cash equivalents and investments	'	'	'	'	'
Investments, Amortized Cost	'	'	'	'	238
Investments, Estimated Fair Value	'	'	'	'	$238

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Assets:	'	'	'
Total, Estimated Fair Value	$19,198	'	$26,419
Transfer of assets between levels	0	0	'
Recurring fair value measurement \| Level 1	'	'	'
Assets:	'	'	'
Money market fund	357	'	5,356
Total, Estimated Fair Value	11,702	'	16,782
Recurring fair value measurement \| Level 1 \| U.S. treasury notes	'	'	'
Assets:	'	'	'
Available for sale securities	11,108	'	11,188
Recurring fair value measurement \| Level 1 \| Certificates of deposit	'	'	'
Assets:	'	'	'
Available for sale securities	237	'	238
Recurring fair value measurement \| Level 2	'	'	'
Assets:	'	'	'
Total, Estimated Fair Value	7,496	'	9,637
Recurring fair value measurement \| Level 2 \| U.S. government agency securities	'	'	'
Assets:	'	'	'
Available for sale securities	7,496	'	9,637
Recurring fair value measurement \| Total	'	'	'
Assets:	'	'	'
Money market fund	357	'	5,356
Total, Estimated Fair Value	19,198	'	26,419
Recurring fair value measurement \| Total \| U.S. treasury notes	'	'	'
Assets:	'	'	'
Available for sale securities	11,108	'	11,188
Recurring fair value measurement \| Total \| U.S. government agency securities	'	'	'
Assets:	'	'	'
Available for sale securities	7,496	'	9,637
Recurring fair value measurement \| Total \| Certificates of deposit	'	'	'
Assets:	'	'	'
Available for sale securities	$237	'	$238

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (Nonrecurring fair value measurement, USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Nonrecurring fair value measurement	'	'
Fair Value Measurements on a Nonrecurring Basis	'	'
Impairment loss related to the assets held for sale	$0	$27,000

Convertible_Preferred_Stock_an1

Convertible Preferred Stock and Stockholders' Equity (Details) (USD $)	6 Months Ended			0 Months Ended			0 Months Ended
	Jun. 30, 2013	29-May-13	Jul. 02, 2013	Apr. 19, 2013	Jul. 02, 2013	29-May-13	Jul. 02, 2013	Jul. 02, 2013	Jul. 02, 2013
		Pfizer note	Common stock	Series A preferred stock	Series A-1 preferred stock	Series A-1 preferred stock	IPO	IPO	IPO
			Warrant		Pfizer note	Pfizer note	Common stock	Series A preferred stock	Series A-1 preferred stock
Convertible preferred stock and stockholders' deficit	'	'	'	'	'	'	'	'	'
Preferred stock, shares authorized	'	'	'	17,000,000	'	6,750,000	'	'	'
Share price of preferred stock (in dollars per share)	'	'	$6.99	$1	'	$1.16	'	'	'
Proceeds from issuance of preferred stock, net of issuance costs	$16,827,000	'	'	$16,900,000	'	'	'	'	'
Stock issuance costs	1,067,000	'	'	100,000	'	'	'	'	'
Conversion rate	'	'	'	0.143	'	0.143	'	'	'
Outstanding principal amount	'	$7,800,000	'	'	'	'	'	'	'
Number of shares of convertible preferred stock converted into common stock	'	'	'	'	966,218	'	9,210,999	8,244,781	966,218

Stock_Compensation_Details

Stock Compensation (Details) (USD $)	6 Months Ended	12 Months Ended	0 Months Ended		6 Months Ended	0 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jan. 02, 2014	Jun. 25, 2013	Jun. 30, 2014	Jun. 25, 2013
	Jun. 30, 2014	Dec. 31, 2013	2013 Plan	2013 Plan	2013 Plan	2008 Incentive Stock Option and Restricted Stock Plan
Stock compensation	'	'	'	'	'	'
Shares reserved and approved for issuance	'	'	'	1,100,000	'	'
Shares reserved under previous plan and subsequently transferred to new plan	'	'	'	54,129	'	54,129
Percentage of increase in the number of shares reserved and available for issuance	'	'	'	2.50%	'	'
Increase in the number of shares of stock reserved and available for issuance	'	'	383,935	'	'	'
Expiration period	'	'	'	'	'10 years	'
Period from cessation of employment within which options expire if not exercised	'	'	'	'	'90 days	'
Number of Options	'	'	'	'	'	'
Outstanding at the beginning of period (in shares)	1,401,101	'	'	'	'	'
Granted (in shares)	251,500	'	'	'	'	'
Forfeited or expired (vested and unvested) (in shares)	-38,771	'	'	'	'	'
Exercised (in shares)	-87,590	'	'	'	'	'
Outstanding at the end of the period (in shares)	1,526,240	1,401,101	'	'	'	'
Weighted-Average Price Per Share	'	'	'	'	'	'
Outstanding at the beginning of period (in dollars per share)	$9.59	'	'	'	'	'
Granted (in dollars per share)	$14.67	'	'	'	'	'
Forfeited or expired (vested and unvested) (in dollars per share)	$6.17	'	'	'	'	'
Exercised (in dollars per share)	$1.62	'	'	'	'	'
Outstanding at the end of the period (in dollars per share)	$10.98	$9.59	'	'	'	'
Weighted-Average Remaining Contractual Term (Years)	'	'	'	'	'	'
Outstanding at the end of the period	'8 years 8 months 8 days	'8 years 11 months 12 days	'	'	'	'
Aggregate Intrinsic Value	'	'	'	'	'	'
Outstanding at the end of the period (in dollars)	$8,150,000	$7,755,000	'	'	'	'
Information about the stock option plan	'	'	'	'	'	'
Number of Options, vested and expected to vest (in shares)	1,465,510	'	'	'	'	'
Number of Options, exercisable (in shares)	609,994	'	'	'	'	'
Weighted-Average Price Per Share, vested and expected to vest (in dollars per share)	$10.90	'	'	'	'	'
Weighted-Average Price Per Share, exercisable (in dollars per share)	$4.59	'	'	'	'	'
Weighted-Average Remaining Contractual Term, vested and expected to vest	'8 years 8 months 1 day	'	'	'	'	'
Weighted-Average Remaining Contractual Term, exercisable	'7 years 9 months 11 days	'	'	'	'	'
Aggregate Intrinsic Value, vested and expected to vest (in dollars)	7,928,000	'	'	'	'	'
Aggregate Intrinsic Value, exercisable (in dollars)	6,956,000	'	'	'	'	'
Additional disclosures	'	'	'	'	'	'
Unrecognized compensation cost (in dollars)	$8,400,000	'	'	'	'	'
Weighted-average period over which remaining unrecognized compensation cost will be recognized	'3 years	'	'	'	'	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
Income Taxes (Details) (USD $)	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Taxes	'	'	'	'
Provision for income taxes	$0	$0	$0	$0

Net_Loss_Per_Common_Share_Deta

Net Loss Per Common Share (Details)	0 Months Ended	6 Months Ended	12 Months Ended
Net Loss Per Common Share (Details)	Jun. 11, 2013	Jun. 30, 2014	Dec. 31, 2013
Net Loss Per Common Share	'	'	'
Reverse stock split ratio of shares outstanding	0.1431	'	'
Net Loss Per Common Share	'	'	'
Total potential dilutive shares	'	1,825,287	1,695,494
Warrants for common stock	'	'	'
Net Loss Per Common Share	'	'	'
Total potential dilutive shares	'	285,920	277,690
Common shares under option	'	'	'
Net Loss Per Common Share	'	'	'
Total potential dilutive shares	'	1,526,240	1,401,101
Unvested restricted stock	'	'	'
Net Loss Per Common Share	'	'	'
Total potential dilutive shares	'	13,127	16,703