Achillion Pharmaceuticals 10-Q 12 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 01, 2013
Document Information [Line Items]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'ACHN	'
Entity Registrant Name	'ACHILLION PHARMACEUTICALS INC	'
Entity Central Index Key	'0001070336	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	96,675,513

Balance_Sheets

Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$25,630	$18,526
Marketable securities	114,138	46,884
Accounts and other receivables	36	277
Prepaid expenses and other current assets	2,129	2,180
Total current assets	141,933	67,867
Marketable securities	32,692	12,008
Fixed assets, net	1,205	1,247
Deferred financing costs	79	256
Restricted cash	152	152
Total assets	176,061	81,530
Current liabilities:	'	'
Accounts payable	4,845	4,276
Accrued expenses	6,367	4,510
Current portion of long-term debt	326	350
Total current liabilities	11,538	9,136
Long-term debt	110	347
Total liabilities	11,648	9,483
Commitments and contingencies	'	'
Stockholders' Equity:	'	'
Common Stock, $.001 par value; 200,000 shares authorized: 96,669 and 79,626 shares issued and outstanding at September 30, 2013 and December 31, 2012, respectively	97	80
Additional paid-in capital	532,631	394,675
Accumulated deficit	-368,324	-322,727
Accumulated other comprehensive (loss) income	9	19
Total stockholders' equity	164,413	72,047
Total liabilities and stockholders' equity	$176,061	$81,530

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Per Share data, unless otherwise specified
Common stock, par value	$0.00	$0.00
Common Stock, shares authorized	200,000	200,000
Common Stock, shares issued	96,669	79,626
Common Stock, shares outstanding	96,669	79,626

Statements_of_Comprehensive_Lo

Statements of Comprehensive Loss (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue	'	'	'	$2,489
Operating expenses	'	'	'	'
Research and development	11,342	12,641	36,629	30,562
General and administrative	2,734	2,647	9,353	7,965
Total operating expenses	14,076	15,288	45,982	38,527
Loss from operations	-14,076	-15,288	-45,982	-36,038
Other income (expense)	'	'	'	'
Interest income	166	49	429	168
Interest expense	-9	-16	-44	-53
Net loss	-13,919	-15,255	-45,597	-35,923
Total comprehensive loss (Note 11)	($13,769)	($15,222)	($45,607)	($35,858)
Basic and diluted net loss per share (Note 5)	($0.14)	($0.20)	($0.49)	($0.50)
Weighted average number of shares used in computing basic and diluted net loss per share	96,648	74,647	93,066	72,099

Statements_of_Cash_Flows

Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities	'	'
Net loss	($45,597)	($35,923)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	296	319
Non-cash stock based compensation	4,320	2,669
Premium on purchases of marketable securities	-3,243	-622
Amortization of premium on marketable securities	1,677	314
Changes in operating assets and liabilities:	'	'
Accounts and other receivables	241	-360
Prepaid expenses and other assets	219	-867
Accounts payable	569	1,071
Accrued expenses	1,857	2,541
Deferred revenue	'	-2,489
Net cash used in operating activities	-39,661	-33,347
Cash flows from investing activities	'	'
Purchases of fixed assets	-245	-628
Purchases of marketable securities	-148,512	-71,051
Maturities of marketable securities	62,130	65,450
Net cash (used in) provided by investing activities	-86,627	-6,229
Cash flows from financing activities	'	'
Proceeds from sale of common stock, net of issuance costs	133,211	41,682
Proceeds from exercise of stock options	337	2,126
Proceeds from sale of common stock under Employee Stock Purchase Plan	105	88
Borrowings of debt	'	609
Repayments of debt	-261	-198
Net cash provided by financing activities	133,392	44,307
Net increase in cash and cash equivalents	7,104	4,731
Cash and cash equivalents, beginning of period	18,526	16,110
Cash and cash equivalents, end of period	25,630	20,841
Supplemental disclosure of cash flow information	'	'
Cash paid for interest	36	46
Supplemental disclosure of noncash financing activities	'	'
Cashless exercise of warrants	$47	$14,106

Nature_of_the_Business

Nature of the Business	9 Months Ended
	Sep. 30, 2013
Nature of the Business	'
	1. Nature of the Business
	Achillion Pharmaceuticals, Inc. (the “Company”) was incorporated on August 17, 1998 in Delaware. The Company was established to discover, develop and commercialize innovative anti-infective drug therapies. The Company is devoting substantially all of its efforts towards product research and development.
	The Company incurred losses of $354,462 from inception through September 30, 2013 and had an accumulated deficit of $368,324 at September 30, 2013, which includes preferred stock dividends recognized until the Company’s initial public offering in 2006. The Company has funded its operations primarily through the sale of equity securities.
	The Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to support its current operating plan through at least September 30, 2014. However, the Company’s operating plan may change as a result of many factors, including but not limited to:
		•	the costs involved in the clinical development, manufacturing and formulation of ACH-3102, ACH-2684, ACH-3422, and if the Food and Drug Administration’s, or FDA’s, clinical hold is removed, further clinical development of sovaprevir;
		•	the scope of and costs associated with entering into cooperative study arrangements, or CSAs, if any, for the collaborative development of its drug candidates in combination with others’ drug candidates;
		•	the costs involved in obtaining regulatory approvals for the Company’s drug candidates;
		•	the scope, prioritization and number of programs the Company pursues;
		•	the costs involved in preparing, filing, prosecuting, maintaining, enforcing and defending patent and other intellectual property claims;
		•	the Company’s ability to raise incremental debt or equity capital, including any changes in the credit or equity markets that may impact its ability to obtain capital in the future;
		•	the Company’s acquisition and development of new technologies and drug candidates; and
		•	competing technological and market developments currently unknown to the Company.
	In June 2013, the FDA, placed a clinical hold on sovaprevir after elevations in liver enzymes were noted in a phase I healthy subject drug-drug interaction study evaluating the effects of concomitant administration of sovaprevir with ritonavir-boosted atazanavir. In accordance with the clinical hold, the FDA provided that no new clinical trials that included dosing with sovaprevir could be initiated, however, the FDA allowed continued enrollment and treatment of patients in the phase II -007 clinical trial evaluating 12-weeks of sovaprevir in combination with ACH-3102 and ribavirin for patients with treatment-naive genotype 1 HCV. In September 2013, after reviewing our response, the FDA stated that although all issues identified in the June 2013 letter had been addressed, it had concluded that the removal of the clinical hold was not warranted. The FDA requested, among other things, additional analysis to more fully characterize sovaprevir pharmacokinetics and the intrinsic and extrinsic factors that may lead to higher than anticipated exposures of sovaprevir or other potential toxicities in addition to the observed liver enzyme elevations. The FDA also requested the Company’s proposed plan for future clinical trials in combination with other directly-acting antivirals. At the request of the FDA, the Company plans to submit its proposed plan for analyzing the additional clinical, non-clinical and pharmacokinetic data requested before year-end, and if that analysis plan is approved by the FDA, submit a complete response during the first half of 2014.

Accounting_Standards_Updates

Accounting Standards Updates	9 Months Ended
	Sep. 30, 2013
Accounting Standards Updates	'
	2. Accounting Standards Updates
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income.” This standard requires additional disclosures regarding the reporting of reclassifications out of accumulated other comprehensive income. This ASU is effective for reporting periods beginning after December 15, 2012. The Company evaluated this pronouncement effective January 1, 2013 and determined the further breakout of accumulated other comprehensive income is immaterial to the Company’s financial statements.

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Basis of Presentation	'
	3. Basis of Presentation
	The accompanying unaudited financial statements of the Company should be read in conjunction with the audited financial statements and notes as of and for the year ended December 31, 2012 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 20, 2013. The accompanying financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) for interim financial information, in accordance with the instructions to Form 10-Q and the guidance in Article 10 of Regulation S-X. Accordingly, since they are interim financial statements, the accompanying financial statements do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. The accompanying financial statements reflect all adjustments, consisting of normal recurring adjustments, that are, in the opinion of management, necessary for a fair statement of the results of operations for the interim periods presented. Interim results are not necessarily indicative of results for a full year.
	The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements and notes thereto. A discussion of the Company’s critical accounting policies and management estimates is described in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in Part I, Item 2 of this quarterly report on Form 10-Q.

Financing_Activities

Financing Activities	9 Months Ended
	Sep. 30, 2013
Financing Activities	'
	4. Financing Activities
	Public Offering
	In February 2013, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Citigroup Global Markets, Inc. and Leerink Swann LLC as representatives of the several underwriters named therein (the “Underwriters”), related to a public offering of shares of the Company’s common stock, par value $.001 per share, at a price of $8.40 per share less underwriting discounts and commissions (the “Offering”). The Company issued and sold to the Underwriters an aggregate of 16,894 shares of common stock in connection with the Offering. The Offering resulted in net proceeds to the Company of $133,211.

Earnings_Loss_Per_Share_EPS

Earnings (Loss) Per Share ("EPS")	9 Months Ended
	Sep. 30, 2013
Earnings (Loss) Per Share ("EPS")	'
	5. Earnings (Loss) Per Share (“EPS”)
	Basic EPS is calculated in accordance with Accounting Standards Codification (“ASC”) 260, Earnings Per Share, by dividing net income or loss attributable to common stockholders by the weighted average common stock outstanding. Diluted EPS is calculated by adjusting weighted average common shares outstanding for the dilutive effect of common stock options and warrants. In periods in which a net loss is recorded, no effect is given to potentially dilutive securities, since the effect would be antidilutive. Securities that could potentially dilute basic EPS in the future were not included in the computation of diluted EPS because to do so would have been antidilutive. Potentially dilutive securities were as follows during the nine months ended September 30, 2013 and 2012:
		Nine Months
		Ended September 30,
		2013		2012
		(in thousands)
	Stock Options:
	Weighted average number		7,809		5,807
	Warrants:
	Weighted average number		5,348		6,033
	Potentially dilutive securities outstanding as of September 30, 2013 and 2012 are as follows:
		September 30,
		2013		2012
		(in thousands)
	Stock Options		7,250		5,704
	Warrants		5,338		5,369
	Total potentially dilutive securities outstanding		12,588		11,073

Collaboration_Arrangements

Collaboration Arrangements	9 Months Ended
	Sep. 30, 2013
Collaboration Arrangements	'
	6. Collaboration Arrangements
	GCA Therapeutics, Ltd.
	In February 2010, the Company entered into a license agreement (the “Agreement”) with GCA Therapeutics, Ltd. (“GCAT”) for elvucitabine, the Company’s nucleoside reverse transcriptase inhibitor for the treatment of both hepatitis B virus (“HBV”) infection and human immunodeficiency virus (“HIV”) infection. The Agreement was amended and restated in March 2010. The exclusive license grants GCAT the right, through a Chinese joint venture with Tianjing Institute of Pharmaceutical Research, to clinically develop and commercialize elvucitabine in mainland China, Hong Kong and Taiwan.
	Under the terms of the Agreement, GCAT, through a sublicense agreement with a Chinese joint venture, T&T Pharma Co., Ltd., has assumed all development and regulatory responsibility and associated costs for elvucitabine. The Company did not receive any payment upon entry into the agreement. Upon the first commercial sale of a licensed product, GCAT is obligated to pay $100 to the Company. Further, the Company will be eligible to receive royalties up to 15% of net sales in those territories.
	The Company does not believe that the milestone specified under the Agreement is substantive as achievement of the milestone is based solely on the performance of GCAT and does not relate to any past or future performance by the Company. Because the Company has no performance obligations under the Agreement, it intends to recognize revenue related to the milestone payment upon achievement of the milestone by GCAT. However, there can be no assurance that GCAT will achieve the milestone or that the Company will receive the related revenue. This Agreement shall be effective, unless earlier terminated, until the expiration of the last to expire royalty term.
	Ora, Inc.
	In October 2012, the Company entered into a license and development agreement (the “Ora Agreement”) with Ora, Inc. (“Ora”) for the worldwide development and commercialization of ACH-702 delivered topically or locally. The Ora Agreement was amended in April 2013. Under the terms of the Ora Agreement, Ora will assume development and regulatory responsibility and associated costs for ACH-702. Upon initiation of the agreement, the Company received a one-time license fee of $100, which was recognized as revenue upon the completion of the technology transfer by the Company. The Company is eligible to receive up to $4,000 in development milestones and up to $7,000 in commercialization milestones, in each case assuming specified objectives are achieved, as well as royalties up to 3.5% of net sales. The Company has no further obligations under the Ora Agreement.
	The Ora Agreement includes the right to sublicense any or all of the licensed rights, subject to the Company’s approval. Ora has agreed to pay the Company 15% of all up-front licensing payments and any other payment allocated to or received by Ora pursuant to any sublicense agreement granted by Ora under this agreement; provided that such payment is not a royalty on net sales and not a development or commercial milestone already due to Achillion. In December 2012, Ora entered into a sublicense agreement with Taejoon Pharmaceutical Co. for the development of ACH-702.
	The Company does not believe that the milestones specified under the Ora Agreement are substantive as achievement of the milestones is based solely on the performance of Ora and its sublicensee(s) and does not relate to any past or future performance by the Company. Because the Company has no performance obligations under the Ora Agreement, it intends to recognize revenue related to the milestone payments upon achievement of the milestone by Ora or its sublicensee(s). The Ora Agreement shall be effective and, unless earlier terminated, will continue until the last sale of each and every licensed product to an unrelated third party by Ora, its affiliate or sublicensee.

Marketable_Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2013
Marketable Securities	'
	7. Marketable Securities
	The Company applies the provisions of ASC 820, Fair Value Measurements and Disclosures, for financial assets and liabilities measured on a recurring basis which requires disclosure that establishes a framework for measuring fair value and expands disclosures in the financial statements. The guidance requires that fair value measurements be classified and disclosed in one of the following three categories:
	Level 1: Quoted prices in active markets for identical assets and liabilities that the reporting entity has the ability to access at the measurement date;
	Level 2: Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly; or
	Level 3: Unobservable inputs.
	The fair value of the Company’s marketable securities of $146,830 and $58,892 as of September 30, 2013 and December 31, 2012, respectively, is valued based on level 2 inputs. The Company’s investments consist mainly of corporate debt securities. Fair value is determined by taking into consideration valuations obtained from third-party pricing services. The third-party pricing services utilize industry standard valuation models, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities, and other observable inputs. The Company has assessed these as level 2 within the fair value hierarchy of ASC 820. The Company classifies its entire investment portfolio as available for sale as defined in ASC 320, Debt and Equity Securities. Securities are carried at fair value with the unrealized gains (losses) reported as a separate component of stockholders’ equity within accumulated other comprehensive income.
	The unrealized gain (loss) from marketable securities was $9, $(141) and $19 at September 30, 2013, June 30, 2013 and December 31, 2012, respectively.
	As of September 30, 2013 and December 31, 2012, none of the Company’s investments were determined to be other than temporarily impaired.
	The following table summarizes the Company’s investments:
		September 30, 2013									December 31, 2012
		Amortized		Unrealized		Unrealized			Estimated		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gain		(Loss)			Fair Value		Cost		Gain		(Loss)			Fair Value
	Commercial Paper	$	34,667	$	32		—		$	34,699	$	30,462	$	29		—		$	30,491
	Corporate Debt Securities		109,154		—		(23	)		109,131		26,912		—		(11	)		26,901
	Government and Agency Securities		3,000		—		—			3,000		1,499		1		—			1,500
	Total	$	146,821	$	32		(23	)	$	146,830	$	58,873	$	30		(11	)	$	58,892

Accrued_Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2013
Accrued Expenses	'
	8. Accrued Expenses
	Accrued expenses consist of the following:
		September 30, 2013		December 31, 2012
	Accrued compensation	$	1,550	$	507
	Accrued research and development expenses		4,139		3,280
	Accrued professional fees		325		426
	Other accrued expenses		353		297
	Total	$	6,367	$	4,510
	Accrued research and development expenses are comprised of amounts owed to third-party contract research organizations, clinical investigators, laboratories and data managers for research and development work performed on behalf of the Company.

Debt

Debt	9 Months Ended
	Sep. 30, 2013
Debt	'
	9. Debt
	Debt consists of the following:
		September 30, 2013			December 31, 2012
	2011 Credit Facility, payable in monthly installments through March 2015, with fixed interest of 6.44% to 6.79% per annum	$	436		$	697
	Total debt		436			697
	Less: current portion		(326	)		(350	)
	Total long-term debt, net of current portion	$	110		$	347
	In March 2011, the Company entered into a Master Security Agreement for a $2,000 Capital Expenditure Line of Credit (the “2011 Credit Facility”) with Webster Bank. Under the 2011 Credit Facility, the Company could draw down equipment loan advances for the purchase of new laboratory equipment through March 2013. The purchased laboratory equipment serves as collateral for the 2011 Credit Facility. The Company drew down a total of $1,047 under the 2011 Credit Facility.
	The fair value for this debt would be classified as a level 2 measurement due to the use of inputs based on similar liabilities in the market. At this time, the carrying value approximates fair value.

Stock_Based_Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2013
Stock Based Compensation	'
	10. Stock Based Compensation
	The Company’s 2006 Stock Incentive Plan, or the 2006 Plan, is administered by the Company’s Board of Directors and provides for the grant of incentive stock options, nonstatutory stock options, restricted stock, restricted stock units, stock appreciation rights and other stock-based awards. The Company’s officers, employees, consultants, advisors and directors are eligible to receive awards under the 2006 Plan; however, incentive stock options may only be granted to employees. Options granted are exercisable for a period determined by the Company, but in no event longer than ten years from the date of the grant. Options generally vest ratably over four years. There were 5,423 shares available to be granted under the 2006 Plan as of September 30, 2013.
	A summary of the status of the Company’s stock option activity for the nine months ended September 30, 2013 is presented in the table and narrative below:
		Options			Weighted
					Average
					Exercise
					Price
	Outstanding at January 1, 2013		7,112		$	5.56
	Granted		913			7.59
	Exercised		(128	)		2.64
	Forfeited		(646	)		6.81
	Cancelled		(1	)		6.72
	Outstanding at September 30, 2013		7,250		$	5.75
	Options exercisable at September 30, 2013		4,298		$	4.73
	Weighted-average fair value of options granted during the period				$	5.56
	The Company utilizes the Black-Scholes option pricing model for determining the estimated fair value for stock-based awards. The Black-Scholes model requires the use of assumptions which determine the fair value of the stock-based awards. The assumptions used to value options granted are as follows:
		For the Nine Months Ended
		September 30, 2013		September 30, 2012
	Expected term of option	5.0 - 6.1 years		5.0 - 6.1 years
	Expected volatility	87 - 94%		88 - 90%
	Risk free interest rate	1.01 - 1.71%		0.83 - 1.33%
	Expected dividend yield	0%		0%
	Total compensation expense recorded in the accompanying statements of operations associated with option grants made to employees was $1,185 and $847 for the three months ended September 30, 2013 and 2012, respectively. Total compensation expense recorded in the accompanying statements of operations associated with option grants made to employees was $4,163 and $2,450 for the nine months ended September 30, 2013 and 2012, respectively. The Company recorded no tax benefit related to these options since the Company currently maintains a full valuation allowance on its deferred tax assets.
	As of September 30, 2013, the intrinsic value of the options outstanding was $1,169, of which $1,167 related to vested options and $2 related to unvested options. The intrinsic value of stock options is calculated based on the difference between the exercise prices of the underlying common stock and the quoted stock price of the Company’s common stock as of the reporting date.
	As of September 30, 2013, the total compensation cost related to unvested options not yet recognized in the financial statements is approximately $12,153, net of estimated forfeitures, and the weighted average period over which this amount is expected to be recognized is 1.6 years.

Comprehensive_Loss

Comprehensive Loss	9 Months Ended
	Sep. 30, 2013
Comprehensive Loss	'
	11. Comprehensive Loss
	The Company reports and presents comprehensive loss in accordance with ASC 220, Comprehensive Income, which establishes standards for reporting and display of comprehensive loss and its components in a full set of general purpose financial statements. The objective of the statement is to report a measure of all changes in equity of an enterprise that result from transactions and other economic events of the period other than transactions with owners (comprehensive loss). The Company’s other comprehensive loss arises from net unrealized losses on marketable securities and was immaterial for all periods presented.

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity	'
	12. Stockholders’ Equity
	Changes in stockholders’ equity for the nine months ended September 30, 2013 and 2012 were as follows:
		For the Nine Months Ended September 30,
		2013			2012
	Balance at December 31, 2012 and 2011	$	72,047		$	70,968
	Net loss		(45,597	)		(35,923	)
	Stock based compensation		4,320			2,669
	Exercise of stock options		337			2,126
	Change in unrealized (loss)/gain on marketable securities		(10	)		65
	Issuance of common stock		133,211			41,682
	Issuance of common stock under the Employee Stock Purchase Plan		105			88
	Balance at September 30, 2013 and 2012	$	164,413		$	81,675

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies	'
	13. Commitments and Contingencies
	The Company is a defendant in purported class action lawsuits filed in October 2013 in the United States District Court for the District of Connecticut. The complaints allege violation of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder. The Company believes that it has meritorious defenses to each of the claims in these lawsuits, will deny liability, and intends to vigorously defend the lawsuits. There can be no assurance, however, that the Company will be successful, and an adverse resolution of a lawsuit could have a material adverse effect on the Company’s consolidated financial position and results of operations in the period in which the lawsuit is resolved. The Company is presently unable to predict the outcome of these lawsuits or to reasonably estimate a range of potential losses, if any, related to these lawsuits. In accordance with applicable accounting guidance, the Company will establish a liability for this matter if and when it presents loss contingencies that are both probable and reasonably estimable.

Earnings_Loss_Per_Share_EPS_Ta

Earnings (Loss) Per Share ("EPS") (Tables)	9 Months Ended
	Sep. 30, 2013
Potentially Dilutive Securities	'
	Potentially dilutive securities were as follows during the nine months ended September 30, 2013 and 2012:
		Nine Months
		Ended September 30,
		2013		2012
		(in thousands)
	Stock Options:
	Weighted average number		7,809		5,807
	Warrants:
	Weighted average number		5,348		6,033
Potentially Dilutive Securities Outstanding	'
	Potentially dilutive securities outstanding as of September 30, 2013 and 2012 are as follows:
		September 30,
		2013		2012
		(in thousands)
	Stock Options		7,250		5,704
	Warrants		5,338		5,369
	Total potentially dilutive securities outstanding		12,588		11,073

Marketable_Securities_Tables

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2013
Summary of the Investments	'
	The following table summarizes the Company’s investments:
		September 30, 2013									December 31, 2012
		Amortized		Unrealized		Unrealized			Estimated		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gain		(Loss)			Fair Value		Cost		Gain		(Loss)			Fair Value
	Commercial Paper	$	34,667	$	32		—		$	34,699	$	30,462	$	29		—		$	30,491
	Corporate Debt Securities		109,154		—		(23	)		109,131		26,912		—		(11	)		26,901
	Government and Agency Securities		3,000		—		—			3,000		1,499		1		—			1,500
	Total	$	146,821	$	32		(23	)	$	146,830	$	58,873	$	30		(11	)	$	58,892

Accrued_Expenses_Tables

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2013
Summary of Accrued Expenses	'
	Accrued expenses consist of the following:
		September 30, 2013		December 31, 2012
	Accrued compensation	$	1,550	$	507
	Accrued research and development expenses		4,139		3,280
	Accrued professional fees		325		426
	Other accrued expenses		353		297
	Total	$	6,367	$	4,510

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 30, 2013
Schedule of Debt	'
	Debt consists of the following:
		September 30, 2013			December 31, 2012
	2011 Credit Facility, payable in monthly installments through March 2015, with fixed interest of 6.44% to 6.79% per annum	$	436		$	697
	Total debt		436			697
	Less: current portion		(326	)		(350	)
	Total long-term debt, net of current portion	$	110		$	347

Stock_Based_Compensation_Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Summary of Stock Option Activity	'
	A summary of the status of the Company’s stock option activity for the nine months ended September 30, 2013 is presented in the table and narrative below:
		Options			Weighted
					Average
					Exercise
					Price
	Outstanding at January 1, 2013		7,112		$	5.56
	Granted		913			7.59
	Exercised		(128	)		2.64
	Forfeited		(646	)		6.81
	Cancelled		(1	)		6.72
	Outstanding at September 30, 2013		7,250		$	5.75
	Options exercisable at September 30, 2013		4,298		$	4.73
	Weighted-average fair value of options granted during the period				$	5.56
Assumptions Used for Value Options Granted	'
	The assumptions used to value options granted are as follows:
		For the Nine Months Ended
		September 30, 2013		September 30, 2012
	Expected term of option	5.0 - 6.1 years		5.0 - 6.1 years
	Expected volatility	87 - 94%		88 - 90%
	Risk free interest rate	1.01 - 1.71%		0.83 - 1.33%
	Expected dividend yield	0%		0%

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2013
Changes in Stockholders' Equity	'
	Changes in stockholders’ equity for the nine months ended September 30, 2013 and 2012 were as follows:
		For the Nine Months Ended September 30,
		2013			2012
	Balance at December 31, 2012 and 2011	$	72,047		$	70,968
	Net loss		(45,597	)		(35,923	)
	Stock based compensation		4,320			2,669
	Exercise of stock options		337			2,126
	Change in unrealized (loss)/gain on marketable securities		(10	)		65
	Issuance of common stock		133,211			41,682
	Issuance of common stock under the Employee Stock Purchase Plan		105			88
	Balance at September 30, 2013 and 2012	$	164,413		$	81,675

Nature_of_Business_Additional_

Nature of Business - Additional Information (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Nature Of Business [Line Items]	'	'
Losses incurred from inception	$354,462	'
Accumulated deficit	($368,324)	($322,727)

Financing_Activities_Additiona

Financing Activities - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Feb. 28, 2013	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Financing Activities [Line Items]	'	'	'	'
Common stock, par value	$0.00	$0.00	'	$0.00
Share price	$8.40	'	'	'
Number of common shares issued in public or private offering	16,894	'	'	'
Proceeds from issuance of common stock	$133,211	$133,211	$41,682	'

Potentially_Dilutive_Securitie

Potentially Dilutive Securities Excluded from Computation of Earnings per Share (Detail)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Weighted average number	12,588	11,073
Stock Options	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Weighted average number	7,250	5,704
Stock Options | Weighted Average	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Weighted average number	7,809	5,807
Warrants	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Weighted average number	5,338	5,369
Warrants | Weighted Average	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Weighted average number	5,348	6,033

Potentially_Dilutive_Securitie1

Potentially Dilutive Securities Outstanding (Detail)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total potentially dilutive securities outstanding	12,588	11,073
Stock Options	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total potentially dilutive securities outstanding	7,250	5,704
Warrants	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total potentially dilutive securities outstanding	5,338	5,369

Collaboration_Arrangements_Add

Collaboration Arrangements - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Oct. 31, 2012	Sep. 30, 2013
GCAT | Maximum	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'
Percentage of royalty receivable on net sales	'	15.00%
GCAT | License	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'
Future milestone revenue	'	100
Ora Agreement	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'
License revenue	100	'
Percentage of up front sub license fees	'	15.00%
Ora Agreement | Maximum	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'
Percentage of royalty receivable on net sales	3.50%	'
Ora Agreement | Development Milestone | Maximum	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'
Future milestone revenue	4,000	'
Ora Agreement | Commercialization Milestones | Maximum	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'
Future milestone revenue	$7,000	'

Marketable_Securities_Addition

Marketable Securities - Additional Information (Detail) (USD $)	6 Months Ended	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'	'
Unrealized (loss) gain from marketable securities	($141)	$9	$19
Fair Value, Inputs, Level 2	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'
Fair value of marketable securities	'	$146,830	$58,892

Summary_of_the_Investments_Det

Summary of the Investments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$146,821	$58,873
Unrealized Gain	32	30
Unrealized (Loss)	-23	-11
Estimated Fair Value	146,830	58,892
Commercial Paper	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	34,667	30,462
Unrealized Gain	32	29
Estimated Fair Value	34,699	30,491
Corporate Debt Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	109,154	26,912
Unrealized (Loss)	-23	-11
Estimated Fair Value	109,131	26,901
Government and Agency Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	3,000	1,499
Unrealized Gain	'	1
Estimated Fair Value	$3,000	$1,500

Accrued_Expenses_Detail

Accrued Expenses (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Accrued Liabilities [Line Items]	'	'
Accrued compensation	$1,550	$507
Accrued research and development expenses	4,139	3,280
Accrued professional fees	325	426
Other accrued expenses	353	297
Total	$6,367	$4,510

Debt_Detail

Debt (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Line of Credit Facility [Line Items]	'	'
Total debt	$436	$697
Less: current portion	-326	-350
Total long-term debt, net of current portion	110	347
2011 Credit Facility	'	'
Line of Credit Facility [Line Items]	'	'
Total debt	$436	$697

Debt_Parenthetical_Detail

Debt (Parenthetical) (Detail) (2011 Credit Facility)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
2011 Credit Facility	'	'
Line of Credit Facility [Line Items]	'	'
Credit Facility, interest rate minimum	6.44%	6.44%
Credit Facility, interest rate maximum	6.79%	6.79%
Debt instrument, maturity year	1-Mar-15	1-Mar-15

Debt_Additional_Information_De

Debt - Additional Information (Detail) (2011 Credit Facility, USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2011
2011 Credit Facility	'	'
Line of Credit Facility [Line Items]	'	'
Line of Credit Facility, maximum borrowing capacity	'	$2,000
Line of Credit Facility, expiration date	'2013-03	'
Line of Credit Facility drawn amount	$1,047	'

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Intrinsic value of the options outstanding	$1,169	'	$1,169	'
Intrinsic value of options vested	1,167	'	1,167	'
Intrinsic value of options unvested	2	'	2	'
Total compensation cost related to unvested options not yet recognized	12,153	'	12,153	'
Weighted average period amount, expected to be recognized, years	'	'	'1 year 7 months 6 days	'
Stock Options	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Total compensation expense associated with option grants made	$1,185	$847	$4,163	$2,450
2006 Stock Incentive Plan	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Shares of common stock available for grant	5,423	'	5,423	'
2006 Stock Incentive Plan | Stock Options	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Options vested period	'	'	'4 years	'
2006 Stock Incentive Plan | Stock Options | Maximum	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Options exercisable period	'	'	'10 years	'

Companys_Stock_Option_Activity

Company's Stock Option Activity (Detail) (USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013
Options	'
Outstanding at January 1, 2013	7,112
Options, Granted	913
Options, Exercised	-128
Options, Forfeited	-646
Options, Cancelled	-1
Outstanding at September 30, 2013	7,250
Options exercisable at September 30, 2013	4,298
Weighted Average Exercise Price	'
Weighted Average Exercise Price, Outstanding at January 1, 2013	$5.56
Weighted Average Exercise Price, Granted	$7.59
Weighted Average Exercise Price, Exercised	$2.64
Weighted Average Exercise Price, Forfeited	$6.81
Weighted Average Exercise Price, Cancelled	$6.72
Weighted Average Exercise Price, Outstanding at September 30, 2013	$5.75
Weighted Average Exercise Price, Options exercisable at September 30, 2013	$4.73
Weighted Average Exercise Price, Weighted-average fair value of options granted during the period	$5.56

Assumptions_Used_to_Value_Opti

Assumptions Used to Value Options Granted (Detail)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected volatility, minimum	87.00%	88.00%
Expected volatility, maximum	94.00%	90.00%
Expected dividend yield	0.00%	0.00%
Minimum	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected term of option	'5 years	'5 years
Risk free interest rate	1.01%	0.83%
Maximum	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected term of option	'6 years 1 month 6 days	'6 years 1 month 6 days
Risk free interest rate	1.71%	1.33%

Changes_in_Stockholders_Equity

Changes in Stockholders' Equity (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stockholders Equity [Line Items]	'	'	'	'
Balance at December 31, 2012 and 2011	'	'	$72,047	$70,968
Net loss	-13,919	-15,255	-45,597	-35,923
Stock based compensation	'	'	4,320	2,669
Exercise of stock options	'	'	337	2,126
Change in unrealized (loss)/gain on marketable securities	'	'	-10	65
Issuance of common stock	'	'	133,211	41,682
Issuance of common stock under the Employee Stock Purchase Plan	'	'	105	88
Balance at September 30, 2013 and 2012	$164,413	$81,675	$164,413	$81,675