Esperion Therapeutics (ESPR) 10-Q 6 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - $ / shares	Aug. 01, 2015	Jun. 30, 2015
Document and Entity Information
Entity Registrant Name		Esperion Therapeutics, Inc.
Entity Central Index Key		1,434,868
Document Type		10-Q
Document Period End Date		Jun. 30, 2015
Amendment Flag		false
Current Fiscal Year End Date		--12-31
Entity Current Reporting Status		Yes
Entity Filer Category		Accelerated Filer
Entity Common Stock, Shares Outstanding	22,488,736
Document Fiscal Year Focus		2,015
Document Fiscal Period Focus		Q2
Entity Listing, Par Value Per Share	$ 0.001

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 129,787	$ 85,038
Short-term investments	94,995	20,803
Prepaid clinical development costs	550	366
Other prepaid and current assets	381	492
Total current assets	225,713	106,699
Property and equipment, net	680	780
Intangible assets	56	56
Long-term investments	89,509	35,741
Total assets	315,958	143,276
Current liabilities:
Accounts payable	3,305	2,040
Current portion of long-term debt	1,427	638
Accrued clinical development costs	1,015	1,978
Other accrued liabilities	1,282	835
Total current liabilities	7,029	5,491
Long-term debt, net of discount and issuance costs	3,473	4,231
Total liabilities	$ 10,502	$ 9,722
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized as of June 30, 2015 and December 31, 2014; no shares issued or outstanding at June 30, 2015 and December 31, 2014
Common stock, $0.001 par value; 120,000,000 shares authorized as of June 30, 2015 and December 31, 2014; 22,488,736 shares issued and 22,482,761 outstanding at June 30, 2015 and 20,352,876 shares issued and 20,343,325 outstanding at December 31, 2014	$ 22	$ 20
Additional paid-in capital	433,793	238,031
Accumulated other comprehensive loss	(60)	(59)
Accumulated deficit	(128,299)	(104,438)
Total stockholders' equity	305,456	133,554
Total liabilities and stockholders' equity	$ 315,958	$ 143,276

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2015	Dec. 31, 2014
Condensed Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
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)	$ 0.001	$ 0.001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	22,488,736	20,352,876
Common stock, shares outstanding	22,482,761	20,343,325

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Operating expenses:
Research and development	$ 7,209	$ 6,528	$ 14,599	$ 11,928
General and administrative	5,253	2,726	9,288	5,216
Total operating expenses	12,462	9,254	23,887	17,144
Loss from operations	(12,462)	(9,254)	(23,887)	(17,144)
Interest expense.	(135)	(1)	(269)	(1)
Other income, net	202	17	295	33
Net loss	$ (12,395)	$ (9,238)	$ (23,861)	$ (17,112)
Net loss per common share (basic and diluted) (in dollars per share)	$ (0.55)	$ (0.60)	$ (1.11)	$ (1.11)
Weighted-average shares outstanding (basic and diluted)	22,465,175	15,399,018	21,531,509	15,385,009
Other comprehensive loss:
Unrealized loss on investments	$ (21)	$ (8)	$ (1)	$ (5)
Total comprehensive loss	$ (12,416)	$ (9,246)	$ (23,862)	$ (17,117)

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities
Net loss	$ (23,861)	$ (17,112)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	115	53
Amortization of debt discount and beneficial conversion	15
Amortization of debt issuance costs	16
Amortization of premiums and discounts on investments	178	106
Stock-based compensation expense	4,970	1,676
Loss related to assets held for sale		29
Loss on sale of assets		1
Changes in assets and liabilities:
Prepaids and other assets	(73)	(992)
Accounts payable	1,265	1,789
Other accrued liabilities	(502)	(732)
Net cash used in operating activities	(17,877)	(15,182)
Investing activities
Purchases of investments	(168,134)	(4,800)
Proceeds from sales/maturities of investments	39,995	6,926
Proceeds from sale of assets	6	12
Purchase of property and equipment	(21)	(638)
Net cash used in investing activities	(128,154)	1,500
Financing activities
Proceeds from issuance of common stock, net of issuance costs	189,982
Proceeds from exercise of common stock options	798	142
Proceeds from warrant issuance		78
Proceeds from debt issuance, net of issuance costs		4,869
Net cash provided by financing activities	190,780	5,089
Net increase (decrease) in cash and cash equivalents	44,749	(8,593)
Cash and cash equivalents at beginning of period	85,038	56,537
Cash and cash equivalents at end of period	$ 129,787	$ 47,944

The Company and Basis of Presen

The Company and Basis of Presentation	6 Months Ended
	Jun. 30, 2015
The Company and Basis of Presentation
The Company and Basis of Presentation	1. The Company and Basis of Presentation The Company is an emerging pharmaceutical 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, or bempedoic acid, the Company’s lead product candidate, is an inhibitor of ATP Citrate Lyase, a well-characterized enzyme on the cholesterol biosynthesis pathway; the same pathway that includes HMG-CoA reductase, the enzyme target of statins. ETC-1002 and statins have the same mechanism of action; inhibiting cholesterol biosynthesis, decreasing intracellular cholesterol, up-regulating LDL-receptors, and causing increased LDL-cholesterol clearance and reduced plasma levels of LDL-cholesterol. ETC-1002 is being dev eloped for patients with hyperlipidemia and mixed dyslipidemia. The Company plans to hold an End-of-Phase 2 meeting with the Food and Drug Administration in August 2015, and expects to initiate its Phase 3 clinical program for ETC-1002 in the fourth quarter of 2015. The Company owns the exclusive worldwide rights to ETC-1002. The Company’s primary activities since incorporation have been conducting research and development activities, including nonclinical, preclinical 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 fund operations through public or private equity or debt financings or through other sources, which may include collaborations with third parties. 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. On March 24, 2015, the Company completed an underwritten public offering of 2,012,500 shares of common stock, including 262,500 shares sold pursuant to the full exercise of an over-allotment option granted to the underwriters. All the shares were offered by the Company at a price to the public of $100.00 per share. The aggregate net proceeds received by the Company from the offering were $190.0 million, net of underwriting discounts and commissions and expenses payable by the Company. 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, 2014, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2015
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies In April 2015, the Financial Accounting Standards Board issued Accounting Standards Update 2015-03 which simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts, rather than as a deferred charge. The recognition and measurement guidance for debt issuance costs are not affected by the amendment. The Company early-adopted the amendment effective January 1, 2015, which resulted in a change in the balance sheet presentation of net debt; in prior period disclosures the debt issuance costs related to the Company’s debt liability were presented on the balance sheet as deferred charges within “Other prepaid and current assets”. Upon adoption of the amended guidance, the debt issuance costs associated with the Company’s debt liability are presented on the balance sheet as a direct deduction from the carrying amount of the debt liability. Within the June 30, 2015, and December 31, 2014, balance sheets, “Long-term debt, net of discount and issuance costs” includes $0.1 million and $0.1 million, respectively, of debt issuance costs. 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, 2014.

Debt

Debt	6 Months Ended
	Jun. 30, 2015
Debt
Debt	3. Debt In June 2014, the Company entered into a loan and security agreement (the “Credit Facility”) with Oxford Finance LLC which provided for an initial borrowing of $5.0 million under the term loan (the “Term A Loan”) and additional borrowings of $15.0 million (the “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. Upon achieving positive clinical development results in March 2015, the remaining $15.0 million under the Term B Loan became available to be drawn down, at the Company’s sole discretion, until March 31, 2015. The Company did not elect to draw down the Term B Loan as of March 31, 2015. The 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 the Term A Loan until July 1, 2015, and, thereafter, to pay 36 consecutive, equal monthly installments of principal and interest from August 1, 2015, through July 1, 2018. The Term A Loan bears interest at an annual rate of 6.40%. In addition, a final payment equal to 8.0% of the Term A Loan is due upon the earlier of the maturity date or prepayment of the term loan. 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, so long as the Credit Facility is outstanding, 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 the Term A Loan, the Company issued a 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 the Term A Loan. In addition, the Company incurred debt issuance costs of $0.1 million in connection with the borrowing of the Term A Loan. The debt issuance costs were capitalized and included in long-term debt on the condensed balance sheet at the inception of the Term A Loan, and are amortized to interest expense using the effective-interest method over the same term. As of June 30, 2015, the remaining unamortized discount and debt issuance costs associated with the debt were less than $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) 2015 2016 2017 2018 Total $ During the three and six months ended June 30, 2015, the Company recognized $0.1 million and $0.3 million, respectively of interest expense and made cash interest payments of $0.1 million and $0.2 million, respectively related to the Credit Facility.

Warrants

Warrants	6 Months Ended
	Jun. 30, 2015
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 warrant was recorded at fair value of $0.1 million to additional-paid-in-capital in accordance with Accounting Standards Codification 815-10 based upon the allocation of the debt proceeds. The Company estimated the fair value of the warrant 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 warrant, the risk-free interest rate and the fair value of the common stock underlying the warrant. 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 warrant. 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 warrant. The expected remaining life of the warrant is assumed to be equivalent to its remaining contractual term. Upon the closing of the Company’s initial public offering in July 2013, all warrants exercisable for 1,940,000 shares of Series A preferred stock, at an exercise price of $1.00 per share (unadjusted for stock splits), 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. During the six months ended June 30, 2015, 29,330 warrants were net exercised for 25,445 shares of the Company’s common stock. The remaining 248,360 warrants outstanding as of June 30, 2015, expire in February 2018. As of June 30, 2015, the Company had warrants outstanding that were exercisable for a total of 256,590 shares of common stock at a weighted-average exercise price of $7.25 per share.

Investments

Investments	6 Months Ended
	Jun. 30, 2015
Investments
Investments	5. Investments The following table summarizes the Company’s cash equivalents and investments: June 30, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (in thousands) Cash equivalents: Money market funds $ $ — $ — $ U.S. government agency securities — — Short-term investments: Certificates of deposit — U.S. treasury notes — — U.S. government agency securities ) Long-term investments: Certificates of deposit — U.S. treasury notes ) U.S. government agency securities ) Total $ $ $ ) $ December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (in thousands) Cash equivalents: Money market funds $ $ — $ — $ Short-term investments: Certificates of deposit — — U.S treasury notes — U.S. government agency securities — ) Long-term investments: Certificates of deposit — — U.S. treasury notes — ) U.S. government agency securities — ) Total $ $ $ ) $ At June 30, 2015, and December 31, 2014, 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 loss to other income in the Statements of Operations during the three and six months ended June 30, 2015, and June 30, 2014.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2015
Fair Value Measurements
Fair Value Measurements	6. 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, 2015 Assets: Money market funds $ $ $ — $ — Available-for-sale securities: Certificates of deposit — — U.S. treasury notes — — U.S. government agency securities — — Total assets at fair value $ $ $ $ — December 31, 2014 Assets: Money market funds $ $ $ — $ — Available-for-sale securities: Certificates of deposit — — U.S. treasury notes — — U.S. government agency securities — — Total assets at fair value $ $ $ $ — There were no transfers between Levels 1, 2 or 3 during the three and six months ended June 30, 2015.

Stock Compensation

Stock Compensation	6 Months Ended
	Jun. 30, 2015
Stock Compensation
Stock Compensation	7. Stock Compensation 2013 Stock Option and Incentive Plan In May 2015, the Company’s stockholders approved the amended and restated 2013 Stock Option and Incentive Plan (as amended, the “2013 Plan”) which, among other things, increased the number of shares of common stock reserved for issuance thereunder. The number of shares of common stock available for awards under the 2013 Plan was increased by 923,622 shares from 2,051,378 shares to 2,975,000 shares, plus (i) shares of common stock that are forfeited, cancelled, held back upon the exercise 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 common stock or otherwise terminated (other than by exercise) under the 2013 Plan and the Company’s 2008 Incentive Stock Option and Restricted Stock Plan are added back to the shares of common stock available for issuance under the 2013 Plan, and (ii) on January 1, 2016 and each January 1, thereafter, the number of shares of common stock reserved and available for issuance under the 2013 Plan will be cumulatively increased by 2.5% of the number of shares of common stock outstanding on the immediately preceding December 31, or such lesser number of shares of common stock determined by the compensation committee. The following table summarizes the activity relating to the Company’s options to purchase common stock for the six months ended June 30, 2015: Number of Options Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2014 $ $ Granted $ Forfeited or expired ) $ Exercised ) $ Outstanding at June 30, 2015 $ $ The following table summarizes information about the Company’s stock option plan as of June 30, 2015: Number of Options Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Vested and expected to vest at June 30, 2015 $ $ Exercisable at June 30, 2015 $ $ As of June 30, 2015, there was approximately $33.0 million 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.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2015
Income Taxes
Income Taxes	8. Income Taxes There was no provision for income taxes for the three and six months ended June 30, 2015 and 2014 because the Company has incurred operating losses since inception. At June 30, 2015, the Company concluded that it is not more likely than not that the Company will realize the benefit of its deferred tax assets due to its history of losses. Accordingly, a full valuation allowance has been applied against the net deferred tax assets.

Net Loss Per Common Share

Net Loss Per Common Share	6 Months Ended
	Jun. 30, 2015
Net Loss Per Common Share
Net Loss Per Common Share	9. 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. The shares outstanding at the end of the respective periods presented below were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect: June 30, 2015 December 31, 2014 Warrants for common stock Common shares under option Unvested restricted stock Total potential dilutive shares

The Company and Basis of Pres15

The Company and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2015
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, 2014, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. 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.

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2015
Debt
Schedule of estimated future principal payments due	Years Ending December 31, (in thousands) 2015 2016 2017 2018 Total $

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2015
Investments
Summary of the Company's cash equivalents and investments	June 30, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (in thousands) Cash equivalents: Money market funds $ $ — $ — $ U.S. government agency securities — — Short-term investments: Certificates of deposit — U.S. treasury notes — — U.S. government agency securities ) Long-term investments: Certificates of deposit — U.S. treasury notes ) U.S. government agency securities ) Total $ $ $ ) $ December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (in thousands) Cash equivalents: Money market funds $ $ — $ — $ Short-term investments: Certificates of deposit — — U.S treasury notes — U.S. government agency securities — ) Long-term investments: Certificates of deposit — — U.S. treasury notes — ) U.S. government agency securities — ) Total $ $ $ ) $

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2015
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, 2015 Assets: Money market funds $ $ $ — $ — Available-for-sale securities: Certificates of deposit — — U.S. treasury notes — — U.S. government agency securities — — Total assets at fair value $ $ $ $ — December 31, 2014 Assets: Money market funds $ $ $ — $ — Available-for-sale securities: Certificates of deposit — — U.S. treasury notes — — U.S. government agency securities — — Total assets at fair value $ $ $ $ —

Stock Compensation (Tables)

Stock Compensation (Tables)	6 Months Ended
	Jun. 30, 2015
Stock Compensation
Summary of activity relating to the Company's options to purchase common stock	Number of Options Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2014 $ $ Granted $ Forfeited or expired ) $ Exercised ) $ Outstanding at June 30, 2015 $ $
Summary of information about the stock option plan	Number of Options Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Vested and expected to vest at June 30, 2015 $ $ Exercisable at June 30, 2015 $ $

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2015
Net Loss Per Common Share
Schedule of anti-dilutive securities excluded from the calculation of diluted net loss per share	June 30, 2015 December 31, 2014 Warrants for common stock Common shares under option Unvested restricted stock Total potential dilutive shares

The Company and Basis of Pres21

The Company and Basis of Presentation (Details) - Mar. 24, 2015 - USD ($) $ / shares in Units, $ in Millions	Total
Initial Public Offering
Initial Public Offering
Original issue price (in dollars per share)	$ 100
Net proceeds from the IPO, including proceeds from the exercise of the underwriters' over-allotment option	$ 190
Initial Public Offering | Common stock
Initial Public Offering
Common stock sold (in shares)	2,012,500
Over-allotment option | Common stock
Initial Public Offering
Common stock sold (in shares)	262,500

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Debt
Debt issuance costs	$ 0.1	$ 0.1

Debt (Details)

Debt (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / shares	Jun. 30, 2015USD ($)item$ / shares	Jul. 31, 2013$ / sharesshares
Warrant
Debt
Exercise price (in dollars per share) | $ / shares		$ 7.25	$ 7.25
Series A preferred stock warrant
Debt
Warrants exercisable into stock (in shares) | shares				1,940,000
Exercise price (in dollars per share) | $ / shares				$ 1
Credit Facility
Debt
Maximum borrowing capacity		$ 20,000	$ 20,000
Percentage of final payment equal to amount drawn under the Credit Facility			8.00%
Number of financial covenants associated to the Credit Facility | item			0
Estimated future principal payments due under the Credit Facility
2,015		638	$ 638
2,016		1,604	1,604
2,017		1,709	1,709
2,018		1,049	1,049
Total		5,000	5,000
Interest expense		100	300
Interest payments		100	200
Term A Loan
Debt
Maximum borrowing capacity		$ 5,000	$ 5,000
Period of consecutive equal monthly installments of principal and interest			36 months
Interest rate (as a percent)		6.40%	6.40%
Debt issuance costs		$ 100	$ 100
Term A Loan | Warrant
Debt
Warrants exercisable into stock (in shares) | shares	8,230
Exercise price (in dollars per share) | $ / shares	$ 15.19
Unamortized discount	$ 100
Debt issuance costs		100	100
Term A Loan | Warrant | Maximum
Debt
Unamortized discount		100	100
Term A Loan | Secured promissory notes
Debt
Proceeds from issuance of debt	$ 5,000
Term B Loan
Debt
Maximum borrowing capacity		15,000	15,000
Remaining borrowing capacity		$ 15,000	$ 15,000

Warrants (Details)

Warrants (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jul. 31, 2013
Warrant
Warrants
Exercise price (in dollars per share)	$ 7.25
Warrants exercised	29,330
Number of shares of common stock to be purchased against outstanding warrants	256,590
Series A preferred stock warrant
Warrants
Warrants exercisable into stock (in shares)			1,940,000
Exercise price (in dollars per share)			$ 1
Number of shares of common stock to be purchased against outstanding warrants	248,360
Common stock
Warrants
Exercise price (in dollars per share)		$ 15.19
Common stock | Warrant
Warrants
Warrants exercisable into stock (in shares)	25,445	8,230	277,690
Fair value of warrants		$ 0.1
Share price of common stock (in dollars per share)			$ 6.99

Investments (Details)

Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Cash equivalents and investments
Gross Unrealized Gains	$ 11		$ 11		$ 4
Gross Unrealized Losses	(71)		(71)		(63)
Total, Amortized Cost	238,046		238,046		56,960
Total, Estimated Fair Value	237,986		237,986		56,901
Other income (expense), net	202	$ 17	295	$ 33
Reclassification out of accumulated other comprehensive income (loss)
Cash equivalents and investments
Other income (expense), net	0		0
U.S. government agency securities
Cash equivalents and investments
Investments, Amortized Cost	3,125		3,125
Investments, Estimated Fair Value	3,125		3,125
Short-term investments. | U.S. treasury notes
Cash equivalents and investments
Investments, Amortized Cost	2,000		2,000		9,020
Gross Unrealized Gains					4
Investments, Estimated Fair Value	2,000		2,000		9,024
Short-term investments. | U.S. government agency securities
Cash equivalents and investments
Investments, Amortized Cost	85,079		85,079		8,853
Gross Unrealized Gains	2		2
Gross Unrealized Losses	(22)		(22)		(8)
Investments, Estimated Fair Value	85,059		85,059		8,845
Long-term investments | U.S. treasury notes
Cash equivalents and investments
Investments, Amortized Cost	10,022		10,022		2,494
Gross Unrealized Gains	2		2
Gross Unrealized Losses	(1)		(1)		(5)
Investments, Estimated Fair Value	10,023		10,023		2,489
Long-term investments | U.S. government agency securities
Cash equivalents and investments
Investments, Amortized Cost	68,698		68,698		31,454
Gross Unrealized Gains	5		5
Gross Unrealized Losses	(48)		(48)		(50)
Investments, Estimated Fair Value	68,655		68,655		31,404
Money market funds
Cash equivalents and investments
Cash equivalents, Estimated Fair Value	50,357		50,357		357
Investments, Amortized Cost	50,357		50,357		357
Certificates of deposit | Short-term investments.
Cash equivalents and investments
Investments, Amortized Cost	7,935		7,935		2,934
Gross Unrealized Gains	1		1
Investments, Estimated Fair Value	7,936		7,936		2,934
Certificates of deposit | Long-term investments
Cash equivalents and investments
Investments, Amortized Cost	10,830		10,830		1,848
Gross Unrealized Gains	1		1
Investments, Estimated Fair Value	$ 10,831		$ 10,831		$ 1,848

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Assets:
Total, Estimated Fair Value	$ 237,986	$ 237,986	$ 56,901
Transfer of assets between levels	0	0
Recurring fair value measurement | Level 1
Assets:
Money market fund	50,357	50,357	357
Total, Estimated Fair Value	81,147	81,147	16,652
Recurring fair value measurement | Level 1 | U.S. treasury notes
Assets:
Available for sale securities	12,023	12,023	11,513
Recurring fair value measurement | Level 1 | Certificates of deposit
Assets:
Available for sale securities	18,767	18,767	4,782
Recurring fair value measurement | Level 2
Assets:
Total, Estimated Fair Value	156,839	156,839	40,249
Recurring fair value measurement | Level 2 | U.S. government agency securities
Assets:
Available for sale securities	156,839	156,839	40,249
Recurring fair value measurement | Total
Assets:
Money market fund	50,357	50,357	357
Total, Estimated Fair Value	237,986	237,986	56,901
Recurring fair value measurement | Total | U.S. treasury notes
Assets:
Available for sale securities	12,023	12,023	11,513
Recurring fair value measurement | Total | U.S. government agency securities
Assets:
Available for sale securities	156,839	156,839	40,249
Recurring fair value measurement | Total | Certificates of deposit
Assets:
Available for sale securities	$ 18,767	$ 18,767	$ 4,782

Stock Compensation (Details)

Stock Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended
	May. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Number of Options
Outstanding at the beginning of period (in shares)		1,729,586
Granted (in shares)		702,600
Forfeited or expired (vested and unvested) (in shares)		(10,988)
Exercised (in shares)		(97,915)
Outstanding at the end of the period (in shares)		2,323,283	1,729,586
Weighted-Average Exercise Price Per Share
Outstanding at the beginning of period (in dollars per share)		$ 11.44
Granted (in dollars per share)		65.13
Forfeited or expired (vested and unvested) (in dollars per share)		16.30
Exercised (in dollars per share)		8.15
Outstanding at the end of the period (in dollars per share)		$ 27.79	$ 11.44
Weighted-Average Remaining Contractual Term (Years)
Outstanding at the end of the period		8 years 7 months 6 days	8 years 5 months 5 days
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)		$ 131,325	$ 50,155
Information about the stock option plan
Number of Options, vested and expected to vest (in shares)		2,242,174
Number of Options, exercisable (in shares)		850,861
Weighted-Average Price Per Share, vested and expected to vest (in dollars per share)		$ 27.34
Weighted-Average Price Per Share, exercisable (in dollars per share)		$ 9.58
Weighted-Average Remaining Contractual Term, vested and expected to vest		8 years 6 months 29 days
Weighted-Average Remaining Contractual Term, exercisable		7 years 9 months 7 days
Aggregate Intrinsic Value, vested and expected to vest (in dollars)		$ 127,621
Aggregate Intrinsic Value, exercisable (in dollars)		61,572
Additional disclosures
Unrecognized compensation cost (in dollars)		$ 33,000
Weighted-average period over which remaining unrecognized compensation cost will be recognized		3 years 1 month 6 days
2013 Stock Option and Incentive Plan
Stock compensation
Increase in the number of shares of stock reserved and available for issuance	923,622
Percentage of increase in the number of shares reserved and available for issuance	2.50%
2013 Stock Option and Incentive Plan | Minimum
Stock compensation
Shares reserved and approved for issuance	2,051,378
2013 Stock Option and Incentive Plan | Maximum
Stock compensation
Shares reserved and approved for issuance	2,975,000

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Taxes
Provision for income taxes	$ 0	$ 0	$ 0	$ 0

Net Loss Per Common Share (Deta

Net Loss Per Common Share (Details) - shares	Dec. 31, 2014	Jun. 30, 2015
Net Loss Per Common Share
Total potential dilutive shares	2,025,057	2,585,848
Warrant
Net Loss Per Common Share
Total potential dilutive shares	285,920	256,590
Common shares under option
Net Loss Per Common Share
Total potential dilutive shares	1,729,586	2,323,283
Unvested restricted stock
Net Loss Per Common Share
Total potential dilutive shares	9,551	5,975