Humanigen (HGENQ) 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	'KBIO	'
Entity Registrant Name	'KALOBIOS PHARMACEUTICALS INC	'
Entity Central Index Key	'0001293310	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Smaller Reporting Company	'
Entity Common Stock, Shares Outstanding	'	32,921,962

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$23,297	$10,947
Marketable securities	31,644	9,351
Prepaid expenses and other current assets	1,863	958
Restricted cash	205	'
Total current assets	57,009	21,256
Restricted cash	'	205
Property and equipment, net	375	230
Deferred offering costs	397	2,803
Other assets	156	45
Total assets	57,937	24,539
Current liabilities:	'	'
Accounts payable	3,988	2,448
Accrued compensation	862	628
Deferred rent, short-term	240	101
Accrued research and clinical liabilities	4,138	3,538
Notes payable, short-term	2,383	'
Other accrued liabilities	463	502
Total current liabilities	12,074	7,217
Deferred rent, long-term	'	62
Notes payable, long-term	7,549	9,826
Other liabilities, long-term	'	355
Total liabilities	19,623	17,460
Commitments and contingencies (Note 10)	'	'
Convertible preferred stock, $0.001 par value: no shares and 60,152,555 shares authorized at September 30, 2013, and December 31, 2012, respectively; no shares and 12,329,330 shares issued and outstanding at September 30, 2013, and December 31, 2012, respectively; aggregate liquidation preference of $105,512 at December 31, 2012	'	102,023
Stockholders' equity (deficit):	'	'
Common stock, $0.001 par value: 47,500,000 shares and 80,000,000 shares authorized at September 30, 2013, and December 31, 2012, respectively; 24,296,962 and 2,186,695 shares issued and outstanding at September 30, 2013, and December 31, 2012, respectively	24	2
Additional paid-in capital	168,255	3,317
Accumulated other comprehensive income	14	4
Accumulated deficit	-129,979	-98,267
Total stockholders' equity (deficit)	38,314	-94,944
Total liabilities and stockholders' equity (deficit)	$57,937	$24,539

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Convertible preferred stock, par value	$0.00	$0.00
Convertible preferred stock, shares authorized	0	60,152,555
Convertible preferred stock, shares issued	0	12,329,330
Convertible preferred stock, shares outstanding	0	12,329,330
Convertible preferred stock, shares outstanding, liquidation preference	'	$105,512
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	47,500,000	80,000,000
Common stock, shares issued	24,296,962	2,186,695
Common stock, shares outstanding	24,296,962	2,186,695

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Contract revenue	$9	$69	$40	$6,080
Operating expenses:	'	'	'	'
Research and development	8,995	6,788	24,961	14,238
General and administrative	2,101	1,572	6,060	3,392
Total operating expenses	11,096	8,360	31,021	17,630
Loss from operations	-11,087	-8,291	-30,981	-11,550
Other income (expense):	'	'	'	'
Interest expense	-278	-40	-807	-40
Interest and other income (expense), net	36	-271	76	-222
Net loss	-11,329	-8,602	-31,712	-11,812
Other comprehensive income:	'	'	'	'
Net unrealized gains (losses) on marketable securities	-7	'	10	12
Comprehensive loss	($11,336)	($8,602)	($31,702)	($11,800)
Basic and diluted net loss per common share	($0.47)	($4.05)	($1.48)	($5.71)
Weighted average common shares outstanding used to calculate basic and diluted net loss per common share	24,263,745	2,124,280	21,385,478	2,070,055

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating activities:	'	'
Net loss	($31,712)	($11,812)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	190	147
Amortization of intangible assets	'	83
Noncash interest expense	125	9
Amortization of premium on marketable securities	347	172
Stock based compensation expense	1,008	616
Gains on disposal of fixed assets	'	-146
Change in fair value of preferred stock warrant liability	'	388
Changes in operating assets and liabilities:	'	'
Prepaid expenses and other assets	-906	-200
Accounts payable	1,419	1,817
Accrued compensation	234	-430
Deferred revenue	'	-5,630
Accrued research and clinical liabilities	601	-289
Other liabilities	-106	-39
Deferred rent	77	-34
Net cash used in operating activities	-28,723	-15,348
Investing activities:	'	'
Proceeds from sale of property and equipment	'	170
Purchases of property and equipment	-335	'
Purchase of marketable securities	-46,351	-23,652
Proceeds from maturities and sales of marketable securities	23,721	19,680
Net cash used in investing activities	-22,965	-3,802
Financing activities:	'	'
Payments of deferred offering costs	-29	-1,510
Proceeds from issuance of debt	'	4,840
Proceeds from issuances of Series E preferred stock, net	'	18,845
Proceeds from issuance of common stock	155	54
Proceeds from initial public offering, net of offering costs	63,912	'
Net cash provided by financing activities	64,038	22,229
Net increase in cash and cash equivalents	12,350	3,079
Cash and cash equivalents, beginning of period	10,947	3,338
Cash and cash equivalents, end of period	23,297	6,417
Supplemental cash flow disclosure:	'	'
Cash paid for interest	663	'
Supplemental disclosure of noncash financing activities:	'	'
Conversion of preferred stock to common stock and additional paid-in capital	102,023	'
Reclassification of preferred stock warrants liability to additional paid-in capital	157	'
Issuance of common stock warrants in connection with a loan amendment	130	'
Issuance of preferred stock warrant issued with note payable	'	$79

Nature_of_Operations

Nature of Operations	9 Months Ended
	Sep. 30, 2013
Nature of Operations	'
	1. Nature of Operations
	KaloBios Pharmaceuticals, Inc. (the Company) is a biopharmaceutical company whose primary business is to develop monoclonal antibody therapeutics for diseases that represent a significant burden to society and to patients and their families. The Company’s primary clinical focus is on respiratory diseases and cancer. All of the Company’s assets are located in California.
	The Company has incurred significant losses and had an accumulated deficit of $130.0 million as of September 30, 2013. The Company has financed its operations primarily through the sale of equity securities, debt financing, grants and the payments received under its agreements with Novartis Pharma AG (Novartis) and Sanofi Pasteur S.A. (Sanofi). To date, none of the Company’s product candidates have been approved for sale and therefore the Company has not generated any revenue from product sales. Management expects operating losses to continue for the foreseeable future. As a result, the Company will continue to seek additional capital through equity offerings, debt financing and/or payments under new or existing licensing or collaboration agreements. If sufficient funds on acceptable terms are not available when needed, the Company could be required to significantly reduce its operating expenses and delay, reduce the scope of, or eliminate one or more of its development programs.
	Initial Public Offering and October Offering of Common Stock
	The Company closed its initial public offering (IPO) in February 2013, selling 8,750,000 shares of common stock. The IPO price was $8.00 per share. As a result of the IPO, the Company received gross proceeds of approximately $70.0 million, which resulted in net proceeds to the Company of approximately $61.5 million, after underwriting and other expenses of approximately $8.5 million (comprised of $4.9 million in underwriting discounts and commissions and $3.6 million in other offering expenses). In addition, in connection with the completion of the Company’s IPO, all outstanding convertible preferred stock converted into 13,211,120 shares of common stock.
	The Company closed an equity public offering in October, 2013, selling 8,625,000 shares of common stock. The offering price was $4.00 per share. As a result of the offering , the Company received gross proceeds of $34.5 million, including the exercise of the overallotment option by the Underwriters, which resulted in net proceeds of approximately $32.0 million, after underwriting and other expenses of approximately $2.5 million (comprised of $2.1 million in underwriting discounts and commissions and $0.4 million in other expenses).

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Summary of Significant Accounting Policies	'
	2. Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and include all adjustments necessary for the presentation of our consolidated financial position, comprehensive loss and cash flows for the periods presented. During the Company’s review of the second quarter of 2013 research and development expenses and accruals, certain out-of-period costs primarily related to clinical trial and related expenses were identified. The cumulative adjustment for these out-of-period costs that the Company recorded in the quarter ended June 30, 2013 is $1.3 million. The Company analyzed and assessed the effect of these adjustments in the annual and interim periods in which they should have been recorded, as well as the effect that these errors had, both individually and in the aggregate, on the Company’s reported financial results during the annual and interim periods in which they occurred. This analysis also included their impact on disclosed financial trends and on the Company’s “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in the affected 2012 Annual Report on Form 10-K, and the first and second 2013 quarterly reports on Form 10-Q. Following this analysis and taking into account both quantitative and qualitative factors, the Company believes that the uncorrected out-of-period costs that are disclosed in the Company’s reports are not material to the respective periods in which the errors occurred. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries.
	The financial information filed is unaudited. The December 31, 2012 Condensed Consolidated Balance Sheet was derived from audited financial statements, but does not include all disclosures required by GAAP. The results for interim periods are not necessarily indicative of the results for the entire year or any other interim period. The information in this quarterly report on Form 10-Q should be read in conjunction with the Company’s financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012 filed with the Securities and Exchange Commission, or SEC, on March 29, 2013.
	Reverse Stock Split
	In December 2012, the Company’s board of directors approved a 1-for-3.56147 reverse split of the Company’s issued and outstanding capital stock which became effective on January 15, 2013. Upon the effectiveness of the reverse stock split, (i) every 3.56147 shares of issued and outstanding common stock and preferred stock was decreased to one share of common stock or preferred stock, as applicable, (ii) the number of shares of common stock into which each outstanding option to purchase common stock is exercisable was proportionally decreased on a 1-for-3.56147 basis and the number of shares of preferred stock into which each outstanding warrant is exercisable was proportionally decreased on a 1-for-3.56147 basis and, (iii) the exercise price of each outstanding option to purchase common stock and warrant to purchase preferred stock was proportionately increased. All of the share numbers, share prices, exercise prices and other per share information throughout these financial statements have been adjusted, on a retroactive basis, to reflect this 1-for-3.56147 reverse stock split.
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements and accompanying notes. Actual results could differ materially from those estimates. The Company believes judgment is involved in determining revenue recognition, the fair value-based measurement of stock-based compensation, accruals and warrant valuations. The Company evaluates estimates and assumptions as facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ from these estimates and assumptions, and those differences could be material to the consolidated financial statements.
	Concentration of Credit Risks and Other Uncertainties
	Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk in the event of a default by the related financial institution holding the securities, to the extent of the value recorded in the balance sheet. The Company invests cash that is not required for immediate operating needs primarily in highly liquid instruments with lower credit risk. The Company has established guidelines relating to the quality, diversification, and maturities of securities to enable the Company to manage its credit risk.
	Cash, Cash Equivalents, and Marketable Securities
	The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. The Company’s cash equivalents and marketable securities are available for use in order to meet the Company’s liquidity needs within the next year and so are classified as short-term and available for sale (see Note 3). Securities available for sale are carried at estimated fair value, with unrealized gains and losses reported as part of accumulated other comprehensive income (loss), a separate component of stockholders’ equity (deficit). The Company has estimated the fair value amounts by using available market information. The cost of available-for-sale securities sold is based on the specific-identification method.
	Deferred Offering Costs
	Deferred offering costs included in the balance sheet as of September 30, 2013 and December 31, 2012, consists of legal, accounting, printing and filing fees incurred in the preparation of the Company’s Registration Statements on Form 10-12G , Form S-1, and Form S-3 associated with the Company’s offerings as described above. As of September 30, 2013 and December 31, 2012, the Company had capitalized $0.4 million and $2.8 million of deferred offering costs, respectively, on the consolidated balance sheets. The deferred offering costs were offset against the proceeds from the October offering and IPO in October 2013 and February 2013, respectively.
	Convertible Preferred Stock Warrant Liabilities and Warrants
	Prior to the Company’s IPO, outstanding warrants to purchase shares of the Company’s Series B-2 and Series E preferred stock were classified as other liabilities. The initial liability recorded was adjusted for changes in the fair values of the Company’s preferred stock warrants during each reporting period and was recorded as a component of other income (expense) in the statement of operations for that period.
	Upon the closing of the Company’s initial public offering (IPO) and the conversion of the underlying preferred stock to common stock, the Company’s warrants to purchase shares of Series B-2 preferred stock were converted into warrants to purchase shares of the Company’s common stock. The aggregate fair value of these warrants upon the closing of the IPO was $157,000 which was reclassified from liabilities to additional paid-in capital, a component of stockholders’ equity (deficit), and the Company ceased recording any further related periodic fair value adjustments. The Company estimated the fair values of these warrants using the Black-Scholes option-pricing model, based on the inputs for the estimated fair value of the underlying convertible preferred stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates, expected dividend rates and expected volatility of the price of the underlying convertible preferred stock. These estimates were based on subjective assumptions.
	The warrant to purchase shares of the Company’s Series E preferred stock expired upon the closing of the Company’s IPO in February 2013.
	On June 19, 2013, the Company entered into an amendment (the Amendment) to a loan and security agreement (the Agreement) with MidCap Financial, SBIC, LP (MidCap Financial). In connection with the Amendment, the Company issued a warrant to purchase up to 49,548 shares of the Company’s common stock with an exercise price of $12.11 per share. The warrant expires on the tenth anniversary of its issuance date.
	Research and Development Expenses
	Development costs incurred in the research and development of new products are expensed as incurred, including expenses that may or may not be reimbursed under research and development collaboration agreements. Research and development costs include, but are not limited to, salaries, benefits, stock-based compensation, laboratory supplies, allocated overhead, fees for professional service providers and costs associated with product development efforts, including preclinical studies and clinical trials. Research and development expenses under collaborative agreements approximate or exceed the revenue recognized under such agreements.
	The Company estimates preclinical study and clinical trial expenses based on the services performed, pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered.
	Revenue Recognition
	The Company recognizes revenue when: (i) persuasive evidence of an arrangement exists, (ii) transfer of technology has been completed, delivery has occurred or services have been rendered, (iii) the fee is fixed or determinable, and (iv) collectability is reasonably assured. Payments received in advance of work performed are recorded as deferred revenue and recognized when earned. All revenue recognized to date under the Company’s collaborative agreements has been nonrefundable.
	Multiple Element Arrangements
	The Company evaluates revenue from agreements that have multiple elements to determine whether the components of the arrangement represent separate units of accounting. Management considers whether components of an arrangement represent separate units of accounting based upon whether certain criteria are met, including whether the delivered element has stand-alone value to the customer. To date, all of the Company’s research and development collaboration and license agreements have been assessed to have one unit of accounting. Up-front and license fees received for a combined unit of accounting are deferred and recognized ratably over the projected performance period. Nonrefundable fees where the Company has no continuing performance obligations are recognized as revenue when collection is reasonably assured and all other revenue recognition criteria have been met.
	Research and Development Services
	Internal and external research and development costs incurred in connection with collaboration agreements are recognized as revenue in the same period as the costs are incurred and have been presented on a gross basis because the Company acts as a principal, has the discretion to choose suppliers, bears credit risk, and performs at least part of the services.
	Milestones and Other Contingent Payments
	The Company has adopted the milestone method as described in FASB ASU 2010-17, Milestone Method of Revenue Recognition. Under the milestone method, contingent consideration received from the achievement of a substantive milestone will be recognized in its entirety in the period in which the milestone is achieved. A milestone is defined as an event having all of the following characteristics: (i) there is substantive uncertainty at the date the arrangement is entered into that the event will be achieved; (ii) the event can only be achieved; based in whole or in part on either the company’s performance or a specific outcome resulting from the company’s performance; and (iii) if achieved, the event would result in additional payments being due to the company.
	The Company’s future research and development and license agreements may provide for payments to be paid to the Company upon the achievement of development milestones or success fees. Given the challenges inherent in developing biologic products, there may be substantial uncertainty as to whether any such milestones would be achieved at the time the agreements are executed. In addition, the Company will evaluate whether the development milestones meet all of the conditions to be considered substantive. The conditions include: (1) the consideration is commensurate with either of the following: (a) the vendor’s performance to achieve the milestone or (b) the enhancement of the value of the delivered item or items as a result of a specific outcome resulting from the vendor’s performance to achieve the milestone; (2) it relates solely to past performance; and (3) it is reasonable relative to all the deliverables and payment terms within the arrangement. If the Company considers the development milestones to be substantive, revenue related to such future milestone payments will be recognized as the Company achieves each milestone.
	Stock-Based Compensation Expense
	The Company measures employee and director stock-based compensation expense for stock awards at the grant date, based on the fair value-based measurement of the award, and the expense is recorded over the related service period, generally the vesting period, net of estimated forfeitures. The Company calculates the fair value-based measurement of stock options using the Black-Scholes valuation model and the single-option method and recognizes expense using the straight-line attribution approach.
	The Company accounts for equity instruments issued to nonemployees based on their fair values on the measurement dates using the Black-Scholes option-pricing model. The fair values of the options granted to nonemployees are re-measured as they vest. As a result, the noncash charge to operations for nonemployee options with vesting is affected each reporting period by changes in the fair value of the Company’s common stock.
	Comprehensive Loss
	Comprehensive loss includes the net loss and all changes in stockholders’ deficit during a period, except for those changes resulting from investments by stockholders or distributions to stockholders. Other comprehensive income consists solely of unrealized gains on marketable securities.
	Net Loss Per Common Share
	Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per common share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive.
	The Company’s potential dilutive securities, which include convertible preferred stock, stock options, and warrants, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share and be antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented. The following shares of outstanding potentially dilutive securities have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive:
		As of September 30,
		2013		2012
	Convertible preferred stock		—		12,329,381
	Warrants to purchase common stock		88,545		—
	Warrants to purchase preferred stock		—		55,514
	Options to purchase common stock		1,840,499		1,057,518
			1,929,044		13,442,413

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments	'
	3. Investments
	At September 30, 2013, the amortized cost and fair value of investments, with gross unrealized gains (losses), were as follows:
	(in thousands)	Amortized		Gross		Fair Value
		Cost		Unrealized
				Gains
	Money market funds	$	22,831	$	—	$	22,831
	Federal agency securities		17,922		3		17,925
	Commercial paper		11,739		11		11,750
	Corporate debt securities		1,969		—		1,969
	Total investments	$	54,461	$	14	$	54,475
	Reported as:
	Cash and cash equivalents					$	22,626
	Marketable securities						31,644
	Restricted cash						205
	Total investments					$	54,475
	At December 31, 2012, the amortized cost and fair value of investments, with gross unrealized gains, were as follows:
	(in thousands)	Amortized		Gross		Fair Value
		Cost		Unrealized
				Gains
	Money market funds	$	5,923	$	—	$	5,923
	Federal agency securities		9,347		4		9,351
	Total investments	$	15,270	$	4	$	15,274
	Reported as:
	Cash and cash equivalents					$	5,718
	Marketable securities						9,351
	Restricted cash						205
	Total investments					$	15,274
	There were no realized gains or losses recorded from the sale of marketable securities for the three and nine months ended September 30, 2013.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2013
Fair Value of Financial Instruments	'
	4. Fair Value of Financial Instruments
	Cash, accounts payable, and accrued liabilities are carried at cost, which approximates fair value given their short-term nature. Marketable securities, cash equivalents and warrants to purchase convertible preferred stock are carried at fair value.
	The fair value of financial instruments reflects the amounts that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The fair value hierarchy is based on three levels of inputs that may be used to measure fair value, of which the first two are considered observable, and the third is considered unobservable, as follows:
	Level 1 – Quoted prices in active markets for identical assets or liabilities.
	Level 2 – Inputs other than those included in Level 1 that are directly or indirectly observable, such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
	Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	The Company measures the fair value of financial assets and liabilities using the highest level of inputs that are reasonably available as of the measurement date. The following tables summarize the fair value of financial assets and liabilities (investments and convertible preferred stock warrant liabilities) that are measured at fair value and the classification by level of input within the fair value hierarchy:
		Fair Value Measurements as of
		September 30, 2013
	(in thousands)	Level 1			Level 2		Level 3		Total
	Investments:
	Money market funds	$	22,831		$	—	$	—	$	22,831
	Federal agency securities		—			17,925		—		17,925
	Commercial paper		—			11,750		—		11,750
	Corporate debt securities		—			1,969		—		1,969
	Total investments	$	22,831		$	31,644	$	—	$	54,475
		Fair Value Measurements as of
		December 31, 2012
	(in thousands)	Level 1			Level 2		Level 3		Total
	Investments:
	Money market funds	$	5,923		$	—	$	—	$	5,923
	Federal agency securities		—			9,351		—		9,351
	Total investments	$	5,923		$	9,351	$	—	$	15,274
	Convertible preferred stock warrant liabilities	$	—		$	—	$	157	$	157
	The Company’s Level 2 investments include U.S. government-backed securities, commercial paper, and corporate securities that ) are valued using third-party pricing sources that apply applicable inputs and other relevant data, such as quoted prices, interest rates and yield curves, into their models to estimate fair value. The average remaining maturity of the Company’s Level 2 investments as of September 30, 2013 is less than six months and all of these investments are rated by S&P and Moody’s at AAA or AA+
	The following table presents changes in financial instruments measured at fair value using Level 3 inputs:
		Convertible
		Preferred Stock
		Warrant
		Liabilities
		(in thousands)
	Balance at December 31, 2012	$	157
	Reclassification of preferred stock warrant liabilities to additional paid-in capital in conjunction with the conversion of the convertible preferred stock into common stock upon the closing of the Company’s IPO		(157	)
	Balance at September 30, 2013	$	—
	The estimated fair value of the notes payable as of September 30, 2013, based upon current rates for similar borrowings, as measured using Level 3 inputs, is $8.3 million.

Notes_Payable

Notes Payable	9 Months Ended
	Sep. 30, 2013
Notes Payable	'
	5. Notes Payable
	Loan and Security Agreement
	In September 2012, the Company entered into the Agreement with MidCap Financial, providing for the borrowing of up to $15 million, of which $10 million was required to be drawn. The remaining $5 million may be drawn at the option of the Company. The Agreement provides for the loan to be issued in three tranches: the first tranche of $5 million was issued in September 2012; the second tranche of $5 million was issued in December 2012; and, prior to the amendment described below, the final tranche could have been drawn at the option of the Company no later than June 2013. The loan has a monthly variable interest rate, reset each month, if applicable, as determined by adding to 600 basis points the greater of: (a) one month LIBOR or (b) 3% (the LIBOR floor). Interest on amounts outstanding are payable monthly in arrears. There is an interest only period to December 31, 2013 followed by straight-line principal payments over thirty-six months until December 31, 2016. At the time of final payment, the Company must pay an exit fee of 3% of the drawn amount. Pursuant to the Agreement, the Company provided a first priority security interest in all existing and after-acquired assets, excluding intellectual property. In addition, the terms of the Agreement provided MidCap Financial a warrant to purchase shares of the Company’s Series E convertible preferred stock (Series E Preferred) equal to 4% of the amount drawn down under the facility divided by the Series E Preferred exercise price of $12.11 per share. The warrant expired upon the completion of the Company’s IPO.
	The Company has the right to prepay all or a portion of the borrowed amounts under the Agreement; however, if the Company exercises this option, the Company must pay a prepayment fee determined by multiplying the outstanding loan amount by 5% if the prepayment occurs on or before December 31, 2014, 2% if the prepayment occurs in 2015 and 1% if the prepayment occurs in the final year. In the event of default, upon which all amounts borrowed become immediately due and payable, the Company will be subject to the prepayment fee. An event of default includes, but is not limited to, an occurrence such as a payment default, a material adverse change, insolvency, or a change of control.
	In connection with the Agreement and the first tranche draw down of $5 million in September 2012 and second tranche draw down of $5 million in December 2012, the Company issued a warrant to MidCap Financial to purchase shares of the Company’s Series E Preferred. Contemporaneously with the issuance of the warrant, the Company recorded a debt discount of $79,000.
	Debt issuance costs paid directly to MidCap Financial of $114,000 (financing fees) and the fair value of the warrant issued to MidCap Financial were treated as a discount on the debt and are being accreted using the interest method. Other debt issuance costs for legal fees are included in other assets in the accompanying consolidated balance sheet and are being amortized using the interest method. The accretion of the debt discount and amortization of other debt issuance costs are recorded as non-cash interest expense in the consolidated statements of comprehensive loss.
	In June 2013, the Company entered into the Amendment to extend the draw down date for the final tranche of $5.0 million from June 2013 to May 2014. In addition, the final tranche was changed from an optional draw down to a required draw down. In connection with the Amendment, the Company issued a warrant to purchase up to 49,548 shares of the Company’s common stock with an exercise price of $12.11 per share. The warrant expires on the tenth anniversary of its issuance date. The warrants issued to Midcap Financial had an initial fair value of $130,000, which represent financing fees, and are included in other assets in the accompanying consolidated balance sheet and are being amortized as non-cash interest expense over the remaining term of the Agreement using the effective interest method. The Company estimated the fair values of these warrants using the Black-Scholes option-pricing model, based on the inputs for the estimated fair value of the underlying common stock at the valuation measurement date, the contractual term of the warrant, risk-free interest rates, expected dividend rates and expected volatility of the price of the underlying common stock.
	The Company recorded interest expense related to the borrowings of $807,000 for the nine months ended September 30, 2013. Included in interest expense for this period was interest on principal, amortization of the debt issuance costs, accretion of debt discount, and the accretion of the final exit fee. For the nine months ended September 30, 2013, the effective interest rate on the amounts borrowed under the Agreement, including the accretion of the debt discount and the accretion of the final payment, was 10%.
	Future payments as of September 30, 2013 for balances outstanding under the Agreement are as follows (in thousands):
	Remainder of 2013	$	575
	2014		3,995
	2015		3,699
	2016		3,403
	Total minimum payments		11,672
	Less amount representing interest		(1,672	)
	Notes payable, gross		10,000
	Discount on notes payable		(135	)
	Accretion of the final exit fee payment		67
			9,932
	Less short-term portion of notes payable		(2,383	)
	Long-term notes payable	$	7,549

Sanofi

Sanofi	9 Months Ended
	Sep. 30, 2013
Sanofi	'
	6. Sanofi
	In January 2010, the Company and Sanofi entered into an agreement for the development and commercialization of KB001-A, an investigational new biologic for the treatment and prevention of Pseudomonas aeruginosa (Pa) infections (the Sanofi agreement). Under the terms of the Sanofi agreement, the Company received an initial upfront non-refundable payment of $35 million and received an additional non-refundable payment of $5 million that represented a second installment of the upfront fees due to the Company under the agreement upon completion of a sublicense negotiation with a third party in August 2011. The Company may also receive development, regulatory and commercial contingent payments for a potential further $250 million, as well as royalties on eventual product sales, if any. These contingent payments do not meet the definition of milestones since they are based solely on Sanofi’s performance and therefore, the milestone method will not be applied to these payments. Sanofi is solely responsible for conducting, at its cost, the research, development, manufacture, and commercialization of the licensed products for the diagnosis, treatment and/or prevention of all human diseases and conditions caused by Pa, except that the Company retains responsibility, at the Company’s cost, for developing and promoting the products for the diagnosis, treatment and/or prevention of Pa in patients with cystic fibrosis (CF) or bronchiectasis. Sanofi has an option to obtain rights to participate in the development and promotion of KB001-A and other licensed products for the diagnosis, treatment and/or prevention of Pa in patients with CF or bronchiectasis, either outside of the U.S. or worldwide, at any time up to 90 days after the delivery by the Company to Sanofi of the final clinical study report from the Company’s Phase 2 clinical trial of KB001-A in Pa-infected patients with CF.
	The agreement will remain in effect until all payment obligations under the agreement end. Sanofi may terminate the agreement for convenience, and either Sanofi or the Company may terminate the agreement for material breach of the agreement by the other party. In the event Sanofi terminates the agreement for convenience or the Company terminates due to Sanofi’s material breach, worldwide rights to develop, manufacture and commercialize licensed products would revert back to the Company, and Sanofi would grant to the Company a license to allow it to develop, manufacture, and commercialize licensed products worldwide, subject to commercially reasonable financial terms to be negotiated by the parties after such termination. In the event that the Company materially breaches the agreement, Sanofi may terminate the agreement or, rather than terminate the agreement, opt to deduct any damages awarded for the Company’s breach against future contingent payments and royalties otherwise payable by Sanofi under the agreement.
	The upfront payment of $40 million was recognized over the estimated period of the Company’s substantive performance obligations under the agreement. For the years ended December 31, 2010 and 2011, the Company estimated that substantive performance obligations under the agreement would be completed by March 31, 2012. During the three-month period ended March 31, 2012, the Company and Sanofi agreed to amend the 2010 agreement as Sanofi requested that the Company perform additional services. Therefore, in the three-month period ended March 31, 2012, the Company revised its estimate to reflect that the substantive performance obligations under the agreement were expected to be completed by June 30, 2012. The substantive performance obligations under the agreement were completed by June 30, 2012.
	Under the terms of the Sanofi agreement, the Company receives specified research and development funding for services performed in connection with KB001-A research and development efforts. Reimbursements received by the Company for these services are recorded as contract revenue when earned as the related services are provided.
	Revenue recognized under the Sanofi agreement was as follows:
		Three Months				Nine Months
		Ended September 30,				Ended September 30,
	(In thousands)	2013		2012		2013		2012
	Contract revenue:
	Amortization of upfront fees	$	—	$	—	$	—	$	5,630
	Reimbursement for development-related activities		9		69		40		450
	Total contract revenue	$	9	$	69	$	40	$	6,080

Warrants_to_Purchase_Common_St

Warrants to Purchase Common Stock	9 Months Ended
	Sep. 30, 2013
Warrants to Purchase Common Stock	'
	7. Warrants to Purchase Common Stock
	On June 19, 2013, the Company issued a warrant to purchase up to 49,548 shares of the Company’s common stock with an exercise price of $12.11 per share. The warrant expires on the tenth anniversary of its issuance date. The Company will classify the initial value of the warrants in equity and be included in other assets in the accompanying consolidated balance sheet and are being amortized over the remaining term of the debt using the effective interest method.
	Warrants to purchase an aggregate of 38,997 shares of common stock at $5.13 per share will expire on October 31, 2015.

Common_Stock_and_Stockholders_

Common Stock and Stockholders' Equity	9 Months Ended
	Sep. 30, 2013
Common Stock and Stockholders' Equity	'
	8. Common Stock and Stockholders’ Equity
	At Market Issuance Sales Agreement
	In September 2013, the Company entered into an At Market Issuance Sales Agreement (ATM Agreement) with MLV & Co LLC (MLV) to issue and sell up to $50.0 million of shares of common stock. Pursuant to the terms of the ATM Agreement, the Company will pay directly to MLV fees of 3% of the gross proceeds of any equity securities sold pursuant to the ATM Agreement. No shares of common stock have been sold pursuant to the ATM Agreement.

Stock_Plans_and_StockBased_Com

Stock Plans and Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Stock Plans and Stock-Based Compensation	'
	9. Stock Plans and Stock-Based Compensation
	2012 Equity Incentive Plan
	As of September 30, 2013, under the 2012 Equity Incentive Plan, the Company may grant additional shares and/or options to purchase up to 1,279,540 shares of common stock to employees, directors, consultants, and other service providers. For options, the per share exercise price may not be less than the fair market value of a Company common share on the date of grant. Options generally vest over four years, expire 10 years from the date of grant, and become exercisable as they vest following the date of grant.
	A summary of stock option activity for the nine months ended September 30, 2013 under all of the Company’s options plans is as follows:
					Weighted
					Average
					Exercise
		Options			Price
	Outstanding at December 31, 2012		1,030,795		$	2.68
	Granted		1,010,326			5.91
	Exercised		(149,147	)		1.05
	Cancelled		(51,475	)		2.92
	Outstanding at September 30, 2013		1,840,499		$	4.58
	Weighted-average fair value of options granted during the period				$	3.19
	Stock-Based Compensation
	The Company recorded stock-based compensation expense in the condensed consolidated statements of comprehensive loss as follows:
		Three Months					Nine Months
		Ended September 30,					Ended September 30,
	(In thousands)	2013			2012		2013		2012
	General and administrative	$	241		$	235	$	500	$	303
	Research and development		213			254		508		313
		$	454		$	489	$	1,008	$	616
	At September 30, 2013, the Company had $4.0 million of total unrecognized compensation expense, net of estimated forfeitures, related to outstanding stock options that will be recognized over a weighted-average period of 2.8 years.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies	'
	10. Commitments and Contingencies
	Guarantees and Indemnifications
	The Company, as permitted under Delaware law and in accordance with its bylaws, has agreed to indemnify its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity. The term of the indemnification period is equal to the officer’s or director’s lifetime. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director and officer liability insurance. This insurance limits the Company’s exposure and may enable it to recover a portion of any future amounts paid.
	The Company has certain agreements with service providers with which it does business that contain indemnification provisions pursuant to which the Company typically agrees to indemnify the party against certain types of third-party claims. The Company accrues for known indemnification issues when a loss is probable and can be reasonably estimated. The Company would also accrue for estimated incurred but unidentified indemnification issues based on historical activity. As the Company has not incurred any indemnification losses to date, there were no accruals for or expenses related to indemnification issues for any period presented.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Basis of Presentation	'
	Basis of Presentation
	The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and include all adjustments necessary for the presentation of our consolidated financial position, comprehensive loss and cash flows for the periods presented. During the Company’s review of the second quarter of 2013 research and development expenses and accruals, certain out-of-period costs primarily related to clinical trial and related expenses were identified. The cumulative adjustment for these out-of-period costs that the Company recorded in the quarter ended June 30, 2013 is $1.3 million. The Company analyzed and assessed the effect of these adjustments in the annual and interim periods in which they should have been recorded, as well as the effect that these errors had, both individually and in the aggregate, on the Company’s reported financial results during the annual and interim periods in which they occurred. This analysis also included their impact on disclosed financial trends and on the Company’s “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in the affected 2012 Annual Report on Form 10-K, and the first and second 2013 quarterly reports on Form 10-Q. Following this analysis and taking into account both quantitative and qualitative factors, the Company believes that the uncorrected out-of-period costs that are disclosed in the Company’s reports are not material to the respective periods in which the errors occurred. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries.
	The financial information filed is unaudited. The December 31, 2012 Condensed Consolidated Balance Sheet was derived from audited financial statements, but does not include all disclosures required by GAAP. The results for interim periods are not necessarily indicative of the results for the entire year or any other interim period. The information in this quarterly report on Form 10-Q should be read in conjunction with the Company’s financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012 filed with the Securities and Exchange Commission, or SEC, on March 29, 2013.
Reverse Stock Split	'
	Reverse Stock Split
	In December 2012, the Company’s board of directors approved a 1-for-3.56147 reverse split of the Company’s issued and outstanding capital stock which became effective on January 15, 2013. Upon the effectiveness of the reverse stock split, (i) every 3.56147 shares of issued and outstanding common stock and preferred stock was decreased to one share of common stock or preferred stock, as applicable, (ii) the number of shares of common stock into which each outstanding option to purchase common stock is exercisable was proportionally decreased on a 1-for-3.56147 basis and the number of shares of preferred stock into which each outstanding warrant is exercisable was proportionally decreased on a 1-for-3.56147 basis and, (iii) the exercise price of each outstanding option to purchase common stock and warrant to purchase preferred stock was proportionately increased. All of the share numbers, share prices, exercise prices and other per share information throughout these financial statements have been adjusted, on a retroactive basis, to reflect this 1-for-3.56147 reverse stock split.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements and accompanying notes. Actual results could differ materially from those estimates. The Company believes judgment is involved in determining revenue recognition, the fair value-based measurement of stock-based compensation, accruals and warrant valuations. The Company evaluates estimates and assumptions as facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ from these estimates and assumptions, and those differences could be material to the consolidated financial statements.
Concentration of Credit Risks and Other Uncertainties	'
	Concentration of Credit Risks and Other Uncertainties
	Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk in the event of a default by the related financial institution holding the securities, to the extent of the value recorded in the balance sheet. The Company invests cash that is not required for immediate operating needs primarily in highly liquid instruments with lower credit risk. The Company has established guidelines relating to the quality, diversification, and maturities of securities to enable the Company to manage its credit risk.
Cash, Cash Equivalents, and Marketable Securities	'
	Cash, Cash Equivalents, and Marketable Securities
	The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. The Company’s cash equivalents and marketable securities are available for use in order to meet the Company’s liquidity needs within the next year and so are classified as short-term and available for sale (see Note 3). Securities available for sale are carried at estimated fair value, with unrealized gains and losses reported as part of accumulated other comprehensive income (loss), a separate component of stockholders’ equity (deficit). The Company has estimated the fair value amounts by using available market information. The cost of available-for-sale securities sold is based on the specific-identification method.
Deferred Offering Costs	'
	Deferred Offering Costs
	Deferred offering costs included in the balance sheet as of September 30, 2013 and December 31, 2012, consists of legal, accounting, printing and filing fees incurred in the preparation of the Company’s Registration Statements on Form 10-12G , Form S-1, and Form S-3 associated with the Company’s offerings as described above. As of September 30, 2013 and December 31, 2012, the Company had capitalized $0.4 million and $2.8 million of deferred offering costs, respectively, on the consolidated balance sheets. The deferred offering costs were offset against the proceeds from the October offering and IPO in October 2013 and February 2013, respectively.
Convertible Preferred Stock Warrant Liabilities and Warrants	'
	Convertible Preferred Stock Warrant Liabilities and Warrants
	Prior to the Company’s IPO, outstanding warrants to purchase shares of the Company’s Series B-2 and Series E preferred stock were classified as other liabilities. The initial liability recorded was adjusted for changes in the fair values of the Company’s preferred stock warrants during each reporting period and was recorded as a component of other income (expense) in the statement of operations for that period.
	Upon the closing of the Company’s initial public offering (IPO) and the conversion of the underlying preferred stock to common stock, the Company’s warrants to purchase shares of Series B-2 preferred stock were converted into warrants to purchase shares of the Company’s common stock. The aggregate fair value of these warrants upon the closing of the IPO was $157,000 which was reclassified from liabilities to additional paid-in capital, a component of stockholders’ equity (deficit), and the Company ceased recording any further related periodic fair value adjustments. The Company estimated the fair values of these warrants using the Black-Scholes option-pricing model, based on the inputs for the estimated fair value of the underlying convertible preferred stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates, expected dividend rates and expected volatility of the price of the underlying convertible preferred stock. These estimates were based on subjective assumptions.
	The warrant to purchase shares of the Company’s Series E preferred stock expired upon the closing of the Company’s IPO in February 2013.
	On June 19, 2013, the Company entered into an amendment (the Amendment) to a loan and security agreement (the Agreement) with MidCap Financial, SBIC, LP (MidCap Financial). In connection with the Amendment, the Company issued a warrant to purchase up to 49,548 shares of the Company’s common stock with an exercise price of $12.11 per share. The warrant expires on the tenth anniversary of its issuance date.
Research and Development Expenses	'
	Research and Development Expenses
	Development costs incurred in the research and development of new products are expensed as incurred, including expenses that may or may not be reimbursed under research and development collaboration agreements. Research and development costs include, but are not limited to, salaries, benefits, stock-based compensation, laboratory supplies, allocated overhead, fees for professional service providers and costs associated with product development efforts, including preclinical studies and clinical trials. Research and development expenses under collaborative agreements approximate or exceed the revenue recognized under such agreements.
	The Company estimates preclinical study and clinical trial expenses based on the services performed, pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered.
Revenue Recognition	'
	Revenue Recognition
	The Company recognizes revenue when: (i) persuasive evidence of an arrangement exists, (ii) transfer of technology has been completed, delivery has occurred or services have been rendered, (iii) the fee is fixed or determinable, and (iv) collectability is reasonably assured. Payments received in advance of work performed are recorded as deferred revenue and recognized when earned. All revenue recognized to date under the Company’s collaborative agreements has been nonrefundable.
	Multiple Element Arrangements
	The Company evaluates revenue from agreements that have multiple elements to determine whether the components of the arrangement represent separate units of accounting. Management considers whether components of an arrangement represent separate units of accounting based upon whether certain criteria are met, including whether the delivered element has stand-alone value to the customer. To date, all of the Company’s research and development collaboration and license agreements have been assessed to have one unit of accounting. Up-front and license fees received for a combined unit of accounting are deferred and recognized ratably over the projected performance period. Nonrefundable fees where the Company has no continuing performance obligations are recognized as revenue when collection is reasonably assured and all other revenue recognition criteria have been met.
	Research and Development Services
	Internal and external research and development costs incurred in connection with collaboration agreements are recognized as revenue in the same period as the costs are incurred and have been presented on a gross basis because the Company acts as a principal, has the discretion to choose suppliers, bears credit risk, and performs at least part of the services.
	Milestones and Other Contingent Payments
	The Company has adopted the milestone method as described in FASB ASU 2010-17, Milestone Method of Revenue Recognition. Under the milestone method, contingent consideration received from the achievement of a substantive milestone will be recognized in its entirety in the period in which the milestone is achieved. A milestone is defined as an event having all of the following characteristics: (i) there is substantive uncertainty at the date the arrangement is entered into that the event will be achieved; (ii) the event can only be achieved; based in whole or in part on either the company’s performance or a specific outcome resulting from the company’s performance; and (iii) if achieved, the event would result in additional payments being due to the company.
	The Company’s future research and development and license agreements may provide for payments to be paid to the Company upon the achievement of development milestones or success fees. Given the challenges inherent in developing biologic products, there may be substantial uncertainty as to whether any such milestones would be achieved at the time the agreements are executed. In addition, the Company will evaluate whether the development milestones meet all of the conditions to be considered substantive. The conditions include: (1) the consideration is commensurate with either of the following: (a) the vendor’s performance to achieve the milestone or (b) the enhancement of the value of the delivered item or items as a result of a specific outcome resulting from the vendor’s performance to achieve the milestone; (2) it relates solely to past performance; and (3) it is reasonable relative to all the deliverables and payment terms within the arrangement. If the Company considers the development milestones to be substantive, revenue related to such future milestone payments will be recognized as the Company achieves each milestone.
Stock-Based Compensation Expense	'
	Stock-Based Compensation Expense
	The Company measures employee and director stock-based compensation expense for stock awards at the grant date, based on the fair value-based measurement of the award, and the expense is recorded over the related service period, generally the vesting period, net of estimated forfeitures. The Company calculates the fair value-based measurement of stock options using the Black-Scholes valuation model and the single-option method and recognizes expense using the straight-line attribution approach.
	The Company accounts for equity instruments issued to nonemployees based on their fair values on the measurement dates using the Black-Scholes option-pricing model. The fair values of the options granted to nonemployees are re-measured as they vest. As a result, the noncash charge to operations for nonemployee options with vesting is affected each reporting period by changes in the fair value of the Company’s common stock.
Comprehensive Loss	'
	Comprehensive Loss
	Comprehensive loss includes the net loss and all changes in stockholders’ deficit during a period, except for those changes resulting from investments by stockholders or distributions to stockholders. Other comprehensive income consists solely of unrealized gains on marketable securities.
Net Loss Per Common Share	'
	Net Loss Per Common Share
	Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per common share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive.
	The Company’s potential dilutive securities, which include convertible preferred stock, stock options, and warrants, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share and be antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented. The following shares of outstanding potentially dilutive securities have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive:
		As of September 30,
		2013		2012
	Convertible preferred stock		—		12,329,381
	Warrants to purchase common stock		88,545		—
	Warrants to purchase preferred stock		—		55,514
	Options to purchase common stock		1,840,499		1,057,518
			1,929,044		13,442,413

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2013
Antidilutive Securities Excluded From Computation Of Earning Per Share	'
	The following shares of outstanding potentially dilutive securities have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive:
		As of September 30,
		2013		2012
	Convertible preferred stock		—		12,329,381
	Warrants to purchase common stock		88,545		—
	Warrants to purchase preferred stock		—		55,514
	Options to purchase common stock		1,840,499		1,057,518
			1,929,044		13,442,413

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Amortized Cost and Fair Value of Investments with Gross Unrealized Gains	'
	At September 30, 2013, the amortized cost and fair value of investments, with gross unrealized gains (losses), were as follows:
	(in thousands)	Amortized		Gross		Fair Value
		Cost		Unrealized
				Gains
	Money market funds	$	22,831	$	—	$	22,831
	Federal agency securities		17,922		3		17,925
	Commercial paper		11,739		11		11,750
	Corporate debt securities		1,969		—		1,969
	Total investments	$	54,461	$	14	$	54,475
	Reported as:
	Cash and cash equivalents					$	22,626
	Marketable securities						31,644
	Restricted cash						205
	Total investments					$	54,475
	At December 31, 2012, the amortized cost and fair value of investments, with gross unrealized gains, were as follows:
	(in thousands)	Amortized		Gross		Fair Value
		Cost		Unrealized
				Gains
	Money market funds	$	5,923	$	—	$	5,923
	Federal agency securities		9,347		4		9,351
	Total investments	$	15,270	$	4	$	15,274
	Reported as:
	Cash and cash equivalents					$	5,718
	Marketable securities						9,351
	Restricted cash						205
	Total investments					$	15,274

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value of Financial Assets and Liabilities Measured at Fair Value and Classification by Level of Input	'
	The following tables summarize the fair value of financial assets and liabilities (investments and convertible preferred stock warrant liabilities) that are measured at fair value and the classification by level of input within the fair value hierarchy:
		Fair Value Measurements as of
		September 30, 2013
	(in thousands)	Level 1			Level 2		Level 3		Total
	Investments:
	Money market funds	$	22,831		$	—	$	—	$	22,831
	Federal agency securities		—			17,925		—		17,925
	Commercial paper		—			11,750		—		11,750
	Corporate debt securities		—			1,969		—		1,969
	Total investments	$	22,831		$	31,644	$	—	$	54,475
		Fair Value Measurements as of
		December 31, 2012
	(in thousands)	Level 1			Level 2		Level 3		Total
	Investments:
	Money market funds	$	5,923		$	—	$	—	$	5,923
	Federal agency securities		—			9,351		—		9,351
	Total investments	$	5,923		$	9,351	$	—	$	15,274
	Convertible preferred stock warrant liabilities	$	—		$	—	$	157	$	157
Fair Value of Convertible Preferred Stock Warrant Liability	'
	The following table presents changes in financial instruments measured at fair value using Level 3 inputs:
		Convertible
		Preferred Stock
		Warrant
		Liabilities
		(in thousands)
	Balance at December 31, 2012	$	157
	Reclassification of preferred stock warrant liabilities to additional paid-in capital in conjunction with the conversion of the convertible preferred stock into common stock upon the closing of the Company’s IPO		(157	)
	Balance at September 30, 2013	$	—

Notes_Payable_Tables

Notes Payable (Tables)	9 Months Ended
	Sep. 30, 2013
Future Payments	'
	Future payments as of September 30, 2013 for balances outstanding under the Agreement are as follows (in thousands):
	Remainder of 2013	$	575
	2014		3,995
	2015		3,699
	2016		3,403
	Total minimum payments		11,672
	Less amount representing interest		(1,672	)
	Notes payable, gross		10,000
	Discount on notes payable		(135	)
	Accretion of the final exit fee payment		67
			9,932
	Less short-term portion of notes payable		(2,383	)
	Long-term notes payable	$	7,549

Sanofi_Tables

Sanofi (Tables)	9 Months Ended
	Sep. 30, 2013
Revenue Recognized under Sanofi Agreement	'
	Revenue recognized under the Sanofi agreement was as follows:
		Three Months				Nine Months
		Ended September 30,				Ended September 30,
	(In thousands)	2013		2012		2013		2012
	Contract revenue:
	Amortization of upfront fees	$	—	$	—	$	—	$	5,630
	Reimbursement for development-related activities		9		69		40		450
	Total contract revenue	$	9	$	69	$	40	$	6,080

Stock_Plans_and_StockBased_Com1

Stock Plans and Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Summary of Stock Option Activity	'
	A summary of stock option activity for the nine months ended September 30, 2013 under all of the Company’s options plans is as follows:
					Weighted
					Average
					Exercise
		Options			Price
	Outstanding at December 31, 2012		1,030,795		$	2.68
	Granted		1,010,326			5.91
	Exercised		(149,147	)		1.05
	Cancelled		(51,475	)		2.92
	Outstanding at September 30, 2013		1,840,499		$	4.58
	Weighted-average fair value of options granted during the period				$	3.19
Stock-Based Compensation Expense	'
	The Company recorded stock-based compensation expense in the condensed consolidated statements of comprehensive loss as follows:
		Three Months					Nine Months
		Ended September 30,					Ended September 30,
	(In thousands)	2013			2012		2013		2012
	General and administrative	$	241		$	235	$	500	$	303
	Research and development		213			254		508		313
		$	454		$	489	$	1,008	$	616

Nature_of_Operations_Additiona

Nature of Operations - Additional Information (Detail) (USD $)	9 Months Ended			1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Feb. 28, 2013	Oct. 31, 2013
				IPO	Subsequent Event
					October Offering
Organization and Nature of Operations [Line Items]	'	'	'	'	'
Accumulated deficit	($129,979,000)	'	($98,267,000)	'	'
Common stock share issued	'	'	'	8,750,000	'
Public offering price for common stock	'	'	'	$8	$4
Proceeds from issuance of common stock	155,000	54,000	'	70,000,000	34,500,000
Net proceed from issuance of common stock	'	'	'	61,500,000	32,000,000
Underwriting expenses	'	'	'	8,500,000	2,500,000
Underwriting discounts and commissions	'	'	'	4,900,000	2,100,000
Other offering expenses	'	'	'	$3,600,000	$400,000
Preferred stock converted into common stock	'	'	'	13,211,120	'
Common stock share issued	24,296,962	'	2,186,695	'	8,625,000

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended	1 Months Ended		9 Months Ended
	Jun. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Jun. 30, 2013	Jun. 30, 2013	Sep. 30, 2013
				Loan and Security Agreement	Maximum	Cash and Cash Equivalents
					Loan and Security Agreement	Maximum
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'	'
Cumulative adjustment for out-of-period costs	$1,300,000	'	'	'	'	'
Reverse stock split ratio	'	'	3.56147	'	'	'
Reverse stock split	'	'	'1-for-3.56147 reverse split of the Company's issued and outstanding capital stock which became effective on January 15, 2013.	'	'	'
Highly liquid investments maturity period	'	'	'	'	'	'90 days
Deferred offering costs	'	397,000	2,803,000	'	'	'
Reclassification of preferred stock warrants liability to additional paid-in capital	'	$157,000	'	'	'	'
Issuance of warrant to purchase shares of common stock	'	38,997	'	49,548	49,548	'
Exercise price of warrants issued	'	5.13	'	12.11	'	'
Warrant expiration (in years)	'	'	'	'10 years	'	'

Outstanding_Potentially_Diluti

Outstanding Potentially Dilutive Securities Excluded From Computations of Diluted Net Loss Per Common Share (Detail)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share, amount	1,929,044	13,442,413
Convertible preferred stock	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share, amount	'	12,329,381
Warrants to purchase common stock	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share, amount	88,545	'
Warrants to purchase preferred stock	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share, amount	'	55,514
Options to purchase common stock	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share, amount	1,840,499	1,057,518

Investments_Detail

Investments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$54,461	$15,270
Gross Unrealized Gains	14	4
Fair Value	54,475	15,274
Cash and Cash Equivalents	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value	22,626	5,718
Marketable securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value	31,644	9,351
Restricted cash	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value	205	205
Money market funds	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	22,831	5,923
Fair Value	22,831	5,923
Federal agency securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	17,922	9,347
Gross Unrealized Gains	3	4
Fair Value	17,925	9,351
Commercial paper	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	11,739	'
Gross Unrealized Gains	11	'
Fair Value	11,750	'
Corporate debt securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	1,969	'
Fair Value	$1,969	'

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Schedule Of Marketable Securities [Line Items]	'	'
Realized gains or loses recognized from the sale	$0	$0

Fair_Value_of_Financial_Assets

Fair Value of Financial Assets and Liabilities Measured at Fair Value and Classification by Level of Input (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	$54,475	$15,274
Convertible preferred stock warrant liabilities	'	157
Money market funds	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	22,831	5,923
Federal agency securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	17,925	9,351
Commercial paper	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	11,750	'
Corporate debt securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	1,969	'
Level 1	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	22,831	5,923
Level 1 | Money market funds	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	22,831	5,923
Level 2	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	31,644	9,351
Level 2 | Federal agency securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	17,925	9,351
Level 2 | Commercial paper	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	11,750	'
Level 2 | Corporate debt securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total investments	1,969	'
Level 3	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible preferred stock warrant liabilities	'	$157

Changes_in_Financial_Instrumen

Changes in Financial Instruments Measured at Fair Value Using Level Three Inputs (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Beginning balance	$157
Reclassification of preferred stock warrant liabilities to additional paid-in capital in conjunction with the conversion of the convertible preferred stock into common stock upon the closing of the Company's IPO	($157)

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Additional Information (Detail) (Level 3, USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Level 3	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'
Notes payable, fair value	$8.30

Notes_Payable_Additional_Infor

Notes Payable - Additional Information (Detail) (USD $)	1 Months Ended		9 Months Ended
	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
		Tranche
Notes Payable [Line Items]	'	'	'
Debt discount related to issuance of warrants	'	'	135,000
Debt Issuance Cost Paid	'	'	114,000
Issuance of warrant to purchase shares of common stock	'	'	38,997
Exercise price of warrants issued	'	'	5.13
Loan and Security Agreement	'	'	'
Notes Payable [Line Items]	'	'	'
Maximum amount of borrowing under agreement	'	15,000,000	'
Amount of borrowing required to be drawn	'	10,000,000	'
Amount of borrowing which may be drawn at option of Company	'	5,000,000	'
Number of loan tranches	'	3	'
Variable rate on loan	'	'The loan has a monthly variable interest rate, reset each month, if applicable, as determined by adding to 600 basis points the greater of (a) one month LIBOR or (b) 3% (the LIBOR floor).	'
Spread on Variable rate	'	6.00%	'
LIBOR floor rate	'	3.00%	'
Straight-line principal payments period	'	'36 months	'
Percentage of exit fee of drawn amount	'	3.00%	'
Warrants issued as Percentage of Amount drawn under credit facility	'	4.00%	'
Preferred Stock, issued per share amount	'	$12.11	'
Notes payable, prepayment fee description	'	'	'The Company must pay a prepayment fee determined by multiplying the outstanding loan amount by 5% if the prepayment occurs on or before December 31, 2014, 2% if the prepayment occurs in 2015 and 1% if the prepayment occurs in the final year.
Issuance of warrant to purchase shares of common stock	49,548	'	'
Exercise price of warrants issued	12.11	'	'
Warrant expiration (in years)	'10 years	'	'
Loan and Security Agreement | Series E Preferred Stock	'	'	'
Notes Payable [Line Items]	'	'	'
Debt discount related to issuance of warrants	'	'	79,000
Loan and Security Agreement | December 31, 2014	'	'	'
Notes Payable [Line Items]	'	'	'
Percentage of exit fee of drawn amount	'	'	5.00%
Loan and Security Agreement | 2015	'	'	'
Notes Payable [Line Items]	'	'	'
Percentage of exit fee of drawn amount	'	'	2.00%
Loan and Security Agreement | Final year	'	'	'
Notes Payable [Line Items]	'	'	'
Percentage of exit fee of drawn amount	'	'	1.00%
Loan and Security Agreement | Maximum	'	'	'
Notes Payable [Line Items]	'	'	'
Issuance of warrant to purchase shares of common stock	49,548	'	'
Loan and Security Agreement	'	'	'
Notes Payable [Line Items]	'	'	'
Interest expense related to borrowings	'	'	807,000
Effective interest rate	'	'	10.00%
First Tranche, issued in September 2012 | Loan and Security Agreement	'	'	'
Notes Payable [Line Items]	'	'	'
Amount required to be issued by tranche	'	5,000,000	'
Second Tranche, issued in December 2012 | Loan and Security Agreement	'	'	'
Notes Payable [Line Items]	'	'	'
Amount required to be issued by tranche	'	5,000,000	'
Final tranche, may be drawn at option of Company no later than June 2013 | Loan and Security Agreement	'	'	'
Notes Payable [Line Items]	'	'	'
Amount required to be issued by tranche	'	5,000,000	'
Exercise price of warrants issued	12.11	'	'
Warrant expiration (in years)	'10 years	'	'
Warrants initial fair value	$130,000	'	'
Agreement extend date for final tranche	'2014-05	'	'
Final tranche, may be drawn at option of Company no later than June 2013 | Loan and Security Agreement | Maximum	'	'	'
Notes Payable [Line Items]	'	'	'
Issuance of warrant to purchase shares of common stock	49,548	'	'

Future_Payments_Detail

Future Payments (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]	'	'
Remainder of 2013	$575	'
2014	3,995	'
2015	3,699	'
2016	3,403	'
Total minimum payments	11,672	'
Less amount representing interest	-1,672	'
Notes payable, gross	10,000	'
Discount on notes payable	-135	'
Accretion of the final exit fee payment	67	'
Notes Payable	9,932	'
Less short-term portion of notes payable	-2,383	'
Long-term notes payable	$7,549	$9,826

Sanofi_Additional_Information_

Sanofi - Additional Information (Detail) (Sanofi, USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Sanofi	'
Research and Development Arrangement, Contract to Perform for Others [Line Items]	'
Initial upfront non-refundable payment	$35
Additional non-refundable payment	5
Development, regulatory and commercial contingent payments	250
Maximum days to participate in development and promotion of products	'90 days
Upfront payment being recognized	$40

Revenue_Recognized_under_Sanof

Revenue Recognized under Sanofi Agreement (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
Contract revenue:	'	'	'	'
Amortization of upfront fees	'	'	'	$5,630
Reimbursement for development-related activities	9	69	40	450
Total contract revenue	$9	$69	$40	$6,080

Warrants_to_Purchase_Common_St1

Warrants to Purchase Common Stock - Additional Information (Detail)	9 Months Ended	1 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Jun. 30, 2013
		Loan and Security Agreement	Loan and Security Agreement
			Maximum
Class of Warrant or Right [Line Items]	'	'	'
Issuance of warrant to purchase shares of common stock	38,997	49,548	49,548
Exercise price of warrants issued	5.13	12.11	'
Warrant expiration (in years)	'	'10 years	'
Warrant expiration date	31-Oct-15	'	'

Common_Stock_and_Stockholders_1

Common Stock and Stockholders' Equity - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013
In Millions, except Share data, unless otherwise specified			At Market Issuance Sales Agreement	At Market Issuance Sales Agreement
				Common Stock
				Maximum
Common Stock Equity [Line Items]	'	'	'	'
Equity securities maximum sales value	'	'	'	$50
Agreement fees as percentage of gross proceeds	'	'	3.00%	'
Common stock share sold	24,296,962	2,186,695	0	'

Stock_Plans_and_StockBased_Com2

Stock Plans and Stock-Based Compensation - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Unrecognized compensation expense	$4
Weighted-average period	'2 years 9 months 18 days
2012 Equity Incentive Plan	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of shares authorized to be issued under plan	1,279,540
Vesting period	'4 years
Vesting period expires	'10 years

Summary_of_Stock_Options_Activ

Summary of Stock Options Activity (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Options	'
Options, Outstanding beginning balance	1,030,795
Options, Granted	1,010,326
Options, Exercised	-149,147
Options, Forfeited	-51,475
Options, Outstanding ending balance	1,840,499
Weighted Average Exercise Price	'
Weighted Average Exercise Price, Outstanding beginning balance	$2.68
Weighted Average Exercise Price, Granted	$5.91
Weighted Average Exercise Price, Exercised	$1.05
Weighted Average Exercise Price, Forfeited	$2.92
Weighted Average Exercise Price, Outstanding ending balance	$4.58
Weighted-average fair value of options granted during the period	$3.19

StockBased_Compensation_Expens

Stock-Based Compensation Expense (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
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	$454	$489	$1,008	$616
General and administrative	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	241	235	500	303
Research and development	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expense	$213	$254	$508	$313

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Loss Contingencies [Line Items]	'
Accruals or expenses related to indemnification issues	$0