Kythera Biopharmaceuticals (KYTH) 10-Q 7 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 06, 2015
Document and Entity Information
Entity Registrant Name	KYTHERA BIOPHARMACEUTICALS INC
Entity Central Index Key	1436304
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Current Fiscal Year End Date	-19
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		25,809,307
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$165,870	$29,226
Marketable securities	45,798	70,435
Prepaid expenses and other current assets	1,278	1,498
Total current assets	212,946	101,159
Property and equipment, net	1,942	1,847
Other assets	413	420
Total assets	215,301	103,426
Current liabilities:
Accounts payable	7,414	4,690
Accrued personnel costs	2,885	4,858
Accrued costs for services	3,100	2,103
Accrued interest	998	2,857
Notes payable, current portion	4,518	5,484
Other current liabilities	621	637
Total current liabilities	19,536	20,629
Notes payable-net of current portion	24,396	22,661
Other liabilities	699	698
Total liabilities	44,631	43,988
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.00001 par value, 5,000 shares authorized and none issued and outstanding
Common stock, $0.00001 par value, 300,000 shares authorized, 25,799 and 22,691 shares issued and outstanding at March 31, 2015 and December 31, 2014, respectively
Additional paid in capital	507,335	367,329
Accumulated other comprehensive loss	-15	-53
Accumulated deficit	-336,650	-307,838
Total stockholders' equity	170,670	59,438
Total liabilities and stockholders' equity	$215,301	$103,426

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Per Share data, unless otherwise specified
Condensed Consolidated Balance Sheets
Preferred stock par value (in dollars per share)	$0.00	$0.00
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	300,000	300,000
Common stock, shares issued	25,799	22,691
Common stock, shares outstanding	25,799	22,691

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating expenses:
In-process research and development		$52,757
Research and development	15,266	9,980
Selling, general and administrative	12,496	6,121
Total operating expenses	27,762	68,858
Loss from operations	-27,762	-68,858
Interest income	29	67
Interest expense	-1,079	-654
Net loss	-28,812	-69,445
Other comprehensive (loss) income:
Unrealized net gain on marketable securities	38	8
Comprehensive loss	($28,774)	($69,437)
Per share information:
Net loss, basic and diluted (in dollars per share)	($1.24)	($3.18)
Basic and diluted weighted average shares outstanding (in shares)	23,240	21,836

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating activities
Net loss	($28,812)	($69,445)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of premium on marketable securities	246	265
Amortization of debt discount and issuance cost	275	130
Depreciation	173	28
Non-cash in-process research and development		53,029
Stock-based compensation	4,432	2,911
Changes in assets and liabilities:
Prepaid expenses and other current assets	220	-1,767
Restricted cash		3,888
Other assets	7
Accounts payable and other accrued liabilities	1,616	-1,906
Deferred development funds		-2,147
Other liabilities	-15	-2
Net cash used in operating activities	-21,858	-15,016
Investing activities
Purchases of marketable securities		-9,605
Proceeds from sales of marketable securities	1,929	279
Proceeds from maturities of marketable securities	22,500	6,375
Investment in property and equipment	-268	-42
Net cash provided by (used in) investing activities	24,161	-2,993
Financing activities
Repayment of notes payable	-1,546	-1,420
Proceeds from public offering, net of issuance costs	134,973
Proceeds from common stock option exercises	914	1,080
Net cash provided by (used in) financing activities	134,341	-340
Net increase (decrease) in cash and cash equivalents	136,644	-18,349
Cash and cash equivalents at beginning of period	29,226	111,518
Cash and cash equivalents at end of period	165,870	93,169
Supplemental disclosures
Issuance of common stock to Bayer		31,429
Note payable issued to Bayer at fair value		$21,600

Organization

Organization	3 Months Ended
	Mar. 31, 2015
Organization
Organization
	1. Organization
	KYTHERA Biopharmaceuticals, Inc. (“KYTHERA” or the “Company”) is a biopharmaceutical company focused on the discovery, development and commercialization of novel prescription products for the aesthetic medicine market. The Company’s objective is to develop first-in-class, prescription aesthetic products using an approach that relies on the scientific rigor of biotechnology to address unmet needs in the rapidly-growing market for aesthetic medicine. The Company’s initial focus is on the facial aesthetics market, which comprises the majority of the aesthetics medicine market. The Company’s product candidate, ATX-101, is a potential first-in-class, injectable drug for the reduction of submental fullness, which commonly presents as an undesirable “double chin.”
	KYTHERA was originally incorporated in Delaware in June 2004 under the name Dermion, Inc. It commenced operations in August 2005 and its name was changed to AESTHERx, Inc. In July 2006, the Company changed its name to KYTHERA Biopharmaceuticals, Inc.
	Since commencement of operations in August 2005, the Company has devoted substantially all its efforts to the development of ATX-101, recruiting personnel and raising capital.
	The information included in this quarterly report on Form 10-Q should be read in conjunction with the financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 filed with the Securities Exchange Commission (“SEC”).
	In March 2015, the Company sold 2.6 million shares of common stock, $0.00001 par value per share, in an underwritten public offering at a price to the public of $48.00 per share. The underwriters purchased an additional 391 thousand shares of common stock pursuant to their option to purchase additional shares. The Company received aggregate net proceeds of approximately $134.7 million, after deducting the underwriting discounts and offering related transaction costs incurred. The shares were issued pursuant to registration statement on Form S-3, as amended and supplemented.

Summary_of_Significant_Account

Summary of Significant Accounting Policies and Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Summary of Significant Accounting Policies and Basis of Presentation
Summary of Significant Accounting Policies and Basis of Presentation
	2. Summary of Significant Accounting Policies and Basis of Presentation
	There have been no material changes to the Company’s significant accounting policies during the three months ended March 31, 2015 as compared to the significant accounting policies described in the Company’s audited financial statements included in the Company’s Annual Report on Form 10-K filed with the SEC for the year ended December 31, 2014.
	The accompanying financial information for the three months ended March 31, 2015 and March 31, 2014 are unaudited. The consolidated financial statements include the consolidated accounts of the Company and its wholly-owned subsidiary, KYTHERA Holdings Ltd. (“KHL”), a Bermuda corporation.  Intercompany accounts and transactions have been eliminated in consolidation.  These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, (“GAAP”), and applicable rules and regulations of the SEC regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. In management’s opinion, the unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014, and include all adjustments, which include only normal recurring adjustments necessary for the fair presentation of our condensed consolidated statement of financial position as of March 31, 2015, our condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2015 and 2014 and our condensed consolidated statements of cash flows for the three months ended March 31, 2015 and 2014. The results for interim periods are not necessarily indicative of the results expected for the full fiscal year or any other period(s).
	Reclassifications
	Certain prior year amounts have been reclassified to conform to the current year presentation.
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could materially differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these condensed consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including: expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the financial statements.
	Cash and Cash Equivalents and Marketable Securities
	All highly liquid securities with maturities of 90 days or less from the date of purchase are considered to be cash equivalents. As of March 31, 2015 and December 31, 2014, cash and cash equivalents were comprised of funds invested in cash and money market accounts. The Company maintains cash balances in excess of amounts insured by the Federal Deposit Insurance Corporation, “FDIC”. The accounts are monitored by management to mitigate the risk.
	Investments with maturities of more than 90 days from the date of purchase are classified as marketable securities. Marketable securities are stated at fair value. The Company has classified its entire marketable securities portfolio as available-for-sale securities. Accordingly, any unrealized gain or loss on the investments is reported as a component of accumulated other comprehensive income (loss). The amortized cost of these securities is adjusted for amortization of premiums and accretion of discounts to maturity, as applicable. Such amortizations and accretions are included as a component of interest income. The entire marketable securities portfolio is considered available for use in current operations and, accordingly, all such investments are considered current assets although the stated maturity of individual investments may be more than one year beyond the balance sheet date.
	Realized gains and losses, determined on a specific identification basis, and declines in value, if any, judged to be other-than-temporary on available-for-sale securities are reported as a component of interest income. When securities are sold, any associated unrealized gain or loss previously reported in accumulated other comprehensive income (loss) is reclassified out of stockholders’ equity and recorded in the statement of operations and comprehensive loss for the period. Accrued interest and dividends are included in interest income.
	On a quarterly basis, the Company reviews the available-for-sale securities for other-than-temporary declines in fair value below the amortized cost basis. This evaluation is based on a number of factors including the length of time and extent to which the fair value has been below the cost basis and any adverse conditions related specifically to the security, including any changes to the credit rating of the security. If the Company concludes that an other-than-temporary impairment exists, it recognizes an impairment charge to reduce the investment to fair value and records the related charge as a reduction of interest income. No impairment charges were recognized for the three months ended March 31, 2015 and 2014.
	Property and Equipment
	Property and equipment are recorded at historical cost and consisted of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Cameras	$	923		$	923
	Computer hardware and electronics	475			420
	Furniture and fixtures	345			345
	Software	41			9
	Leasehold improvements	1,465			1,465
	Construction in process	181			—
		3,430			3,162
	Less accumulated depreciation	(1,488		)	(1,315		)
		$	1,942		$	1,847
	Except for leasehold improvements, depreciation is recorded using the straight-line method over the estimated useful lives of the assets (one to five years). Leasehold improvements are being depreciated on a straight line basis over the three year lease term, which is the shorter of the improvements expected useful lives and the lease term.
	The Company reviews its property and equipment assets for impairment in value whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company had no impairments or disposals during the three months ended March 31, 2015 and 2014.
	Concentration of Credit Risk
	Financial instruments, which potentially subject the Company to significant concentrations of credit risk, consist primarily of cash and cash equivalents and marketable securities. The primary objectives for the Company’s investment portfolio are the preservation of capital and the maintenance of liquidity. The Company does not enter into any investment transactions for trading or speculative purposes.
	The Company’s investment policy limits investments to certain types of instruments such as certificates of deposit, money market instruments, obligations issued by U.S. government and U.S. government agencies and corporate debt securities and places restrictions on maturities and concentration by type and issuer. The Company maintains cash balances in excess of amounts insured by the FDIC. The accounts are monitored by management to mitigate the risk.
	Comprehensive Income (Loss)
	Comprehensive income (loss) is comprised of net loss and other comprehensive income (loss). For the three months ended March 31, 2015 and 2014, the only component of other comprehensive income (loss) is net unrealized gains on marketable securities. There were no material reclassifications out of accumulated other comprehensive income (loss) during the three months ended March 31, 2015 and 2014.
	Recent Accounting Pronouncements
	In May 2014, a new standard was issued related to revenue recognition, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The new standard will replace most of the existing revenue recognition standards in U.S. GAAP when it becomes effective on January 1, 2017. The FASB voted on April 1, 2015 to propose a deferral of the effective date of the new revenue standard by one year, but to permit entities to adopt one year earlier if they choose (i.e., the original effective date). For U.S. GAAP public entities, the proposed deferral would result in the new revenue standard being effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2017. Calendar year-end public entities would therefore be required to apply the new revenue guidance beginning in their 2018 interim and annual financial statements. The new standard allows for either “full retrospective” adoption, whereby the new standard is applied to each prior reporting period presented or “modified retrospective” adoption, whereby the new standard is only applied to the most current period presented with the cumulative effect of the change recognized at the date of the initial application. The Company is assessing the potential impact of the new standard on its consolidated statements of financial position and results of operations and comprehensive income (loss) and has not yet selected a transition method.
	In August 2014, a new standard was issued which will require management to evaluate if there is substantial doubt about the entity’s ability to continue as a going concern and, if so, disclose it in both annual and interim reporting periods. The new standard will become effective for the Company’s annual filing for the period ending December 31, 2016 and interim periods thereafter, with early adoption permitted. The Company does not believe the adoption of this accounting standard will have a material impact on the Company’s consolidated financial statements and related disclosures.

Marketable_Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2015
Marketable Securities
Marketable Securities
	3. Marketable Securities
	The Company’s marketable securities held as of March 31, 2015 and December 31, 2014 are summarized below (in thousands):
	Type of security as of March 31, 2015	Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
	Corporate debt securities:
	Financial	$	17,969	$	—	$	(6	)	$	17,963
	Industrial	10,048		1		(5		)	10,044
	Other	17,796		1		(6		)	17,791
	Total available-for-sale securities	$	45,813	$	2	$	(17	)	$	45,798
	Type of security as of December 31, 2014	Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
	U.S. government agency securities	$	2,000	$	1	$	—		$	2,001
	Corporate debt securities:
	Financial	28,067		—		(19		)	28,048
	Industrial	20,625		1		(14		)	20,612
	Other	19,796		—		(22		)	19,774
	Total available-for-sale securities	$	70,488	$	2	$	(55	)	$	70,435
	There were no material realized gains or losses from the sale of marketable securities during the three months ended March 31, 2015 and 2014. At March 31, 2015 and December 31, 2014, the Company believes that the cost basis of our available-for-sale securities were recoverable in all material respects. The unrealized losses as of March 31, 2015 and December 31, 2014 are related to corporate debt securities which the Company has the intent and ability to hold until maturity. The Company does not consider these investments to be other-than-temporarily impaired at March 31, 2015.
	The maturities of the Company’s marketable securities are as follows (in thousands):
		March 31, 2015				December 31, 2014
		Amortized		Estimated Fair		Amortized			Estimated Fair
		Cost		Value		Cost			Value
	Mature in one year or less	$	45,514	$	45,499	$	66,863		$	66,816
	Mature after one year through two years	299		299		3,625			3,619
		$	45,813	$	45,798	$	70,488		$	70,435

Notes_Payable

Notes Payable	3 Months Ended
	Mar. 31, 2015
Notes Payable
Notes Payable
	4. Notes Payable
	Notes payable consisted of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Note payable to Bayer	$	24,396		$	22,166
	Notes payable related to credit facility	4,518			5,979
		28,914			28,145
	Less current portion	(4,518		)	(5,484		)
	Notes payable-net of current portion	$	24,396		$	22,661
	Note Payable to Bayer
	In March 2014, as part of the agreement to acquire the rights to develop and commercialize ATX-101 outside of the United States and Canada, the Company issued a $51.0 million unsecured promissory note to Bayer Consumer Care AG “Bayer”.  The promissory note was subordinated to amounts owed under the Company’s credit facility.  Interest is accrued at 5% per annum and is payable on the anniversary date of the note.  The Company has the option of deferring 80% of the accrued interest, adding any unpaid interest to the principal amount. In connection with the interest payment due in March 2015, the Company paid $510 thousand and elected to defer the remainder of the amount due of $2.0 million, which was then added to the outstanding principal balance of the note. The note is due on the ten year anniversary from issuance, with the option to prepay at any point in time without penalty.
	As the note payable to Bayer bears interest at 5%, which was below the borrowing rate available to the Company at issuance, it was recorded at its fair value of $21.6 million, which is the present value of the future cash flows assuming a borrowing rate of 15%. The difference between face value of $51.0 million and the initial fair value of the note was recorded as a discount and is being amortized over the life of the note utilizing the effective interest method.
	Included in interest expense for the three months ended March 31, 2015 and 2014 was amortization of the debt discount of $190 thousand and $45 thousand, respectively, and interest expense of $635 thousand and $168 thousand, respectively, related to the note payable to Bayer. The balance of accrued interest expense at March 31, 2015 and December 31, 2014 was $174 thousand and $2.1 million, respectively. The balance of the remaining unamortized discount at March 31, 2015 and December 31, 2014 was $28.6 million and $28.8 million, respectively.
	Notes Payable Related to Credit Facility
	On March 21, 2011, the Company executed a debt financing agreement whereby the Company had access to borrow up to $15.0 million of senior loan financing through January 1, 2012. Subsequently, the credit facility was amended to provide for an extension of the drawdown period through February 28, 2013. For each draw, the Company was required to make six months of interest only payments at a fixed rate of 11.5% followed by 30 months of interest and principal payments at a fixed rate of 8.5% and a final payment of 6% of the amount drawn due with the last principal payment. Interest expense related to the notes payable is being recorded over the term of the notes utilizing the effective interest method.  The debt is secured by all the Company’s assets, except for the Company’s intellectual property, which is subject to a negative pledge agreement. Amounts due under the credit facility may be repaid at any time.
	On October 1, 2012, the Company drew $5.0 million and in November 2012, obtained an extension allowing for the draw of the remaining $10.0 million in $5.0 million increments by January 31, 2013 and February 28, 2013. On January 31, 2013 the Company drew down an additional $5.0 million of available funds under its credit facility and on February 28, 2013, the Company drew the remaining $5.0 million.   As of March 31, 2015 $15.0 million had been drawn and there was no further borrowing capacity under this facility.
	Upon entry into the debt financing agreement, the Company issued warrants to purchase 34,000 shares of Series C redeemable convertible preferred stock (“Series C Preferred”) at an exercise price of $13.3530 per share. Upon extension of the credit facility in December 2011, the Company issued a warrant to purchase up to an additional 86,000 shares of its Series D redeemable convertible preferred stock (“Series D Preferred”) at an exercise price of $13.9040 per share. The estimated fair value of the warrants at issuance were recorded as a deferred financing cost offsetting the notes payable liability and is being amortized to interest expense over the expected term of the loan.
	Included in interest expense for the three months ended March 31, 2015 and 2014 was amortization of debt issuance costs of $85 thousand, for both periods, and interest expense of $169 thousand and $356 thousand, respectively, related to the notes payable. The balance of accrued interest expense at March 31, 2015 and December 31, 2014 was $824 thousand and $768 thousand, respectively. The remaining unamortized debt issuance cost at March 31, 2015 and December 31, 2014 was $311 thousand and $396 thousand, respectively.
	See Note 10 “Subsequent Events” regarding the credit facility.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity
Stockholders' Equity
	5. Stockholders’ Equity
	Shares Reserved for Future Issuance
	Shares of the Company’s common stock reserved for future issuance are as follows (in thousands):
		March 31,
		2015
	Common stock awards outstanding	4,018
	Common stock awards available for grant	929
	Total common shares reserved for future issuance	4,947
	ESPP
	In January 2015, the Board approved the 2015 Employee Stock Purchase Plan (“ESPP”), subject to approval by the Company’s shareholders at the annual meeting on June 2, 2015.  The proposed number of shares to be reserved under the plan are 682 thousand, which are not included in the shares reserved for future issuance until the plan is approved. Under the ESPP, employees are offered the option to purchase discounted shares of common stock during six-month offering periods commencing on each March 20 and September 20 following the effective date of the ESPP, except that the first offering period commenced on February 20, 2015 and will end on September 19, 2015. Shares are purchased on the applicable exercise date, generally the last trading day of each offering period. The option price per share of common stock to be paid by a participant upon exercise shall be equal to 85% of the lower of fair market value of the Company’s common stock on either the grant date or the exercise date.
	Stock Awards
	In September 2012, the Company’s board of directors approved the 2012 Equity Incentive Award Plan (“the 2012 Plan”), which became effective upon completion of the Company’s IPO. The 2012 Plan provides for the granting of incentive and nonstatutory stock options, restricted stock, restricted stock units, stock appreciation rights, deferred stock, dividend equivalents, performance awards, stock payments and other stock-based and cash-based awards to its employees, directors, and consultants at the discretion of the compensation committee of the board of directors. The 2012 Plan is the successor to the Amended and Restated 2004 Stock Plan. Any remaining shares available for future issuance under the 2004 Stock Plan are available for issuance under the 2012 Plan. In addition, the plan reserve will automatically increase annually from January 1, 2013 through January 1, 2022 by an amount equal to the smaller of: (a) 1,512,687 shares, (b) four percent of the number of shares of common stock issued and outstanding on the immediately preceding December 31, or (c) an amount determined by the Company’s board of directors. As of March 31, 2015 and December 31, 2014, a total of 5.0 million and 4.1 million shares, respectively, were authorized for grant under the Plan.
	In September 2014, the Company’s board of directors approved the 2014 Employment Commencement Incentive Plan (“the 2014 Plan”), under which up to 900 thousand shares are available for grant. The 2014 Plan provides for the granting of nonstatutory stock options, restricted stock, restricted stock units, performance awards, dividend equivalents, stock payments, stock appreciation rights or other incentive awards or performance share awards to new employees as inducement to enter employment.
	Stock options may be granted with exercise prices not less than the estimated fair market value of the Company’s common stock. Under the 2012 Plan, incentive stock options granted to individuals owning more than 10% of the total combined voting power of all classes of stock (“a 10% stockholder”) are exercisable up to five years from the date of grant. The 2012 Plan provides that the exercise price of any incentive stock option granted to a 10% stockholder cannot be less than 110% of the estimated fair value of the common stock on the date of grant. Except as set forth above, options granted under the Company’s plans expire no later than ten years from the date of grant. Options granted to employees under the Company’s plans vest over periods determined by the board of directors, which generally vest over four years. Additionally, the Company has granted certain performance-based stock option awards and restricted stock units that vest based on the achievement of certain predetermined milestones. Prior to the Company’s initial public offering (IPO), the board of directors determined the estimated fair value of its common stock based on assistance from an independent third-party valuation expert. Since the Company’s IPO, the fair market value of its common stock is the closing share price as reported on the NASDAQ Global Select Market on the date of grant.
	The Company estimates the fair value of its stock-based awards to employees and directors using the Black-Scholes option pricing model. The Black-Scholes model requires the input of complex and subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate and (d) expected dividends. In the past, due to a relatively short amount of company specific historical and implied volatility data, the Company’s estimate of expected volatility was based on the historical volatility of a group of industry peer companies that are publicly traded. As of January 1, 2015, the Company had a sufficient amount of historical information regarding the volatility of its own stock in public markets to rely in part on its own volatility as well as the volatility of the industry peer companies.  When selecting the industry peers, the Company considers enterprise value, risk profiles, position within the industry, and historical public share price information sufficient to meet the expected life of the stock-based awards. The historical volatility data was computed using the daily closing prices during the equivalent period of the calculated expected term of the stock-based awards. The Company has estimated the expected life of its employee stock options using the “simplified” method, whereby, the expected life equals the arithmetic average of the vesting term and the original contractual term of the option due to its lack of sufficient historical data. The risk-free interest rates for periods within the expected life of the option are based on the U.S. Treasury yield curve in effect during the period the options were granted. The Company has never paid, and does not expect to pay dividends in the foreseeable future. The Company accounts for stock options issued to nonemployees using a fair value approach.  The compensation costs of these arrangements are subject to re-measurement over the vesting terms as earned. The Company also grants restricted stock units and the grant date fair value per share of those awards is equal to the closing stock price on the date of grant.
	The Company is also required to estimate forfeitures at the time of grant, and revise those estimates in subsequent periods if actual forfeitures differ from its estimates. The Company uses historical experience to estimate pre-vesting forfeitures and record stock-based compensation expense only for those awards that are expected to vest. To the extent that actual forfeitures differ from the Company’s estimates, the difference is recorded as a cumulative adjustment in the period the estimates were revised. To date, such differences have not been material. For the three months ended March 31, 2015 and 2014, the Company applied forfeiture rates based on the Company’s historical forfeitures.
	A summary of stock option activity for the three months ended March 31, 2015 is as follows:
		Number of		Weighted-
		Options		Average
		(in thousands)		Exercise Price
	Outstanding at December 31, 2014	2,975		$	23.59
	Granted	1,013		38.87
	Exercised	(101	)	9.06
	Cancelled	(10	)	29.47
	Outstanding at March 31, 2015	3,877		$	27.93
	A summary of restricted stock unit (RSU) activity for the three months ended March 31, 2015 is as follows:
		Number of		Weighted-
		RSUs		Average
		(in thousands)		Grant-Date
				Fair Value
	Outstanding at December 31, 2014	138		$	37.92
	Granted	16		45.08
	Vested	(12	)	22.49
	Cancelled	(1	)	44.02
	Outstanding at March 31, 2015	141		$	40.06
	Total equity-based compensation cost recorded in the condensed consolidated statements of operations and comprehensive loss, which includes the value of stock options and RSUs is allocated as follows (in thousands):
		Three Months Ended
		March 31,
		2015			2014
	Research and development	$	2,048		$	1,488
	Selling, general and administrative	2,384			1,423
		$	4,432		$	2,911
	As of March 31, 2015, there was $45.6 million of unrecognized compensation expense related to unvested employee stock option agreements, which is expected to be recognized over a weighted-average period of approximately 3.23 years and $2.3 million related to restricted stock unit agreements which is expected to be recognized over a weighted-average period of approximately 1.13 years. For stock option and restricted stock unit awards subject to graded vesting, the Company recognizes compensation cost on a straight-line basis over the requisite service period for the entire award.

Collaborations_Licensing_and_C

Collaborations, Licensing and Contingencies	3 Months Ended
	Mar. 31, 2015
Collaborations, Licensing and Contingencies
Collaborations, Licensing and Contingencies
	6. Collaborations, Licensing and Contingencies
	Collaboration Arrangements
	A collaborative arrangement is a contractual arrangement that involves a joint operating activity. These arrangements involve two or more parties who are both: (i) active participants in the activity; and (ii) exposed to significant risks and rewards. From time to time, the Company enters into collaborative arrangements and other licensing agreements for its research and development and manufacturing activities. Each is unique in nature and the Company’s significant agreements are discussed below.
	Bayer
	In August 2010, the Company entered into a license agreement with Bayer Consumer Care AG that provided Bayer with an exclusive license to develop, manufacture and commercialize ATX-101 outside of the United States and Canada. In connection with the License Agreement the Company also entered into a related Services, Research, Development and Collaboration Agreement with Bayer’s affiliate, Intendis GmbH. These agreements were referred to jointly as the collaboration arrangement with Bayer, and Bayer Consumer Care AG and Intendis GmbH are referred to jointly as Bayer.
	In March 2014, the Company entered into an agreement whereby it acquired the rights to develop and commercialize ATX-101 outside of the United States and Canada from Bayer.  Under the new agreement, KYTHERA Holdings Ltd., a wholly-owned Bermuda subsidiary of the Company, purchased these rights. As a result of this agreement, Bayer was issued 698 thousand shares of the Company’s common stock valued at $33.0 million based on an average closing stock price of $47.27 over a period set forth in the agreement.  Additionally, the Company issued an unsecured promissory note for $51.0 million, which was subordinated to amounts owed under the Company’s credit facility, bears interest at 5% per annum and is payable no later than 2024. Additionally, Bayer is eligible to receive up to $123.8 million upon the achievement of certain long-term sales milestone payments on annual sales of ATX-101 outside of the United States and Canada.  As of March 31, 2015, the achievement of the related sales levels is not considered to be probable.
	The acquisition date costs allocated to the acquired rights consists of the following (in thousands):
	Fair value of common stock issued	$	31,429
	Fair value of note payable to Bayer	21,600
	Other	(272		)
	Total in-process research and development	$	52,757
	The fair value of the common stock issued is based on the closing price of our common stock on the acquisition date of $45.02 per share. As the note payable to Bayer includes an interest rate which was below the borrowing rate available to the Company at issuance, it was recorded at its fair value of $21.6 million, which is the present value of the future cash flows assuming a borrowing rate of 15%, which approximates the market rate for debt with similar terms and consideration of default and credit risk. Other represents the net impact of the reduction in costs resulting from the residual restricted cash of $967 thousand that reverted to the Company, partially offset by $695 thousand of transaction costs related to the acquisition.
	This transaction was accounted for as an acquisition of a group of assets.  As the acquired rights to ATX-101, represent acquired-in-process research and development, with no alternative future uses, the costs allocated to such rights, $52.8 million, were immediately expensed upon acquisition and reflected as in-process research and development in the condensed consolidated statement of operations and comprehensive loss.  This charge is considered to be a component of research and development expense.
	See Note 4, “Notes Payable” for a more detailed discussion of the promissory note.
	Actelion Pharmaceuticals Ltd. and the Trustees of the University of Pennsylvania
	In February 2015, the Company entered into a licensing arrangement with Actelion Pharmaceuticals Ltd. (“Actelion”) and the Trustees of the University of Pennsylvania (“University of Pennsylvania”) pursuant to which it obtained exclusive worldwide rights to setipiprant, a clinical-stage selective and potent oral antagonist to the prostaglandin D2 (PGD2) receptor and exclusive worldwide rights to certain patent rights owned by the University of Pennsylvania covering the use of PGD2 receptor antagonists for the treatment of hair loss. As part of the agreement, Actelion received an initial payment of $1.5 million and will be eligible to receive up to an additional $25.5 million in potential development and regulatory milestones, as well as royalties on sales if setipiprant is successfully commercialized. The $1.5 million was paid during the three months ended March 31, 2015 and is included in research and development expense in the accompanying condensed consolidated statement of operations and comprehensive loss. University of Pennsylvania will receive an initial payment of $100 thousand, certain annual license maintenance fees beginning in the third year of the agreement, as well as is eligible to receive up to $4.1 million in milestone payments and royalties on sales of products commercialized under the patents provided for in the agreement. As of March 31, 2015, the achievement of the related milestones is not considered to be probable.
	Los Angeles Biomedical Research Institute
	In August 2005, the Company entered into an exclusive license agreement with Los Angeles Biomedical Research Institute at Harbor/UCLA Medical Center, (“LA Biomed”), pursuant to which it obtained a worldwide exclusive license to practice, enforce and otherwise exploit certain patent rights related to the use of the active ingredient in ATX-101. The exclusive license requires the Company to pay LA Biomed a milestone payment of $500 thousand upon receipt of marketing approval of ATX-101, as well as non-royalty sublicense fees equal to 10% of any sublicense income, up to a total of $5.0 million, 50% of which the Company may elect to satisfy through the issuance of capital stock, of which $3.6 million has been incurred and paid. Additionally, upon commercialization of a licensed product or service, the Company is obligated to pay low- to mid- single digit royalties on net product sales of ATX-101.
	Contingencies
	From time to time, the Company may be subject to various litigation and related matters arising in the ordinary course of business. The Company is subject to certain legal proceedings, complaints and claims arising out of the conduct of its business. The Company records a reserve for estimated losses when the loss is probable and the amount can be reasonably estimated. Since the Company believes that it has provided adequate reserves, when necessary, it anticipates that the ultimate outcome of any matters currently pending against the Company will not materially affect the consolidated financial position, results of operations or consolidated cash flows of the Company.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Measurements
Fair Value Measurements
	7. Fair Value Measurements
	The Company applies various valuation approaches in determining the fair value of its financial assets and liabilities within a hierarchy that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. The fair value hierarchy is broken down into three levels based on the source of inputs as follows:
	Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access.
	Level 2—Valuations based on 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 and models for which all significant inputs are observable, either directly or indirectly.
	Level 3—Valuations based on inputs that are unobservable and significant to the overall fair value measurement.
	The availability of observable inputs can vary among the various types of financial assets and liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for financial statement disclosure purposes, the level in the fair value hierarchy within which the fair value measurement is categorized is based on the lowest level input that is significant to the overall fair value measurement.
	At March 31, 2015 and December 31, 2014, the Company had cash equivalents comprised of money market accounts whose value is based using quoted market prices with no adjustments applied. Accordingly, these securities are classified as Level 1. U.S. Government agency securities and corporate debt securities are measured at fair value using Level 2 inputs. These securities are investment grade with maturity dates of two years or less from the balance sheet date.  The Company reviews trading activity and pricing for these investments as of the measurement date. When sufficient quoted pricing for identical securities is not available, the Company uses market pricing and other observable market inputs for similar securities obtained from various third party data providers. These inputs represent quoted prices for similar assets in active markets or these inputs have been derived from observable market data. This approach results in the classification of these securities as Level 2 of the fair value hierarchy.  There were no transfers of assets or liabilities between the fair value measurement levels during the three months ended March 31, 2015 and 2014.
	The following fair value hierarchy table presents information about each major category of the Company’s financial assets measured at fair value on a recurring basis as of March 31, 2015 and December 31, 2014 (in thousands).
		Fair Value Measurement at March 31, 2015 Using:
		Quoted Prices		Significant		Significant		Balance as of
		in Active		Other		Unobservable		March 31, 2015
		Markets for		Observable		Inputs
		Identical		Inputs		(Level 3)
		Assets		(Level 2)
		(Level 1)
	Assets:
	Cash equivalents	$	154,959	$	—	$	—	$	154,959
	Corporate debt securities	—		45,798		—		45,798
	Total	$	154,959	$	45,798	$	—	$	200,757
		Fair Value Measurement at December 31, 2014 Using:
		Quoted Prices		Significant		Significant		Balance as of
		in Active		Other		Unobservable		December 31,
		Markets for		Observable		Inputs		2014
		Identical		Inputs		(Level 3)
		Assets		(Level 2)
		(Level 1)
	Assets:
	Cash equivalents	$	22,691	$	—	$	—	$	22,691
	U.S. government agency securities	—		2,001		—		2,001
	Corporate debt securities	—		68,434		—		68,434
	Total	$	22,691	$	70,435	$	—	$	93,126
	The Company has notes payable, which are liabilities for which fair value is disclosed as of March 31, 2015 and December 31, 2014. Based on the borrowing rates currently available to the Company for debt with similar terms and consideration of default and credit risk, the Company believes that the carrying value of the notes payable related to the credit facility (Level 2) approximates its fair value at March 31, 2015 and December 31, 2014. At March 31, 2015, the Company had a note payable with Bayer at a below market interest rate of 5%.  The carrying value of the note was calculated assuming a discount rate of 15% based on an analysis to determine the market rate available to the Company for similar debt at issuance.  Based on an analysis of various factors at March 31, 2015 and December 31, 2014, including the Company’s cost of equity, the effective interest rate on the credit facility notes payable, the rate of public company structured debt arrangements for companies at a similar stage, its subordinated nature, other debt issuance by investment firms to similar companies and management’s judgment, the Company believes that the carrying value of this note payable approximates its fair value.  Since several of the factors analyzed are considered to be unobservable inputs, this is considered to be a Level 3 valuation.
	The fair values of cash equivalents, accounts payable and accrued liabilities approximate their carrying values due to the short-term nature of these accounts.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Taxes
Income Taxes
	8. Income Taxes
	There is no provision for income taxes because the Company has incurred operating losses since inception. At March 31, 2015 the Company has concluded that it is more likely than not that the Company may not realize the benefit of its deferred tax assets due to its history of losses. Accordingly, the net deferred tax assets have been fully reserved.
	As of March 31, 2015, the Company does not have any accrued interest or penalties related to uncertain tax positions. The Company’s policy is to recognize interest and penalties related to uncertain tax positions in income tax expense. The Company does not have any interest or penalties related to uncertain tax positions in income tax expense for the three months ended March 31, 2015 and 2014. The tax years subsequent to and including 2005 remain open to examination by the major taxing jurisdictions to which the Company is subject.

Basic_and_Diluted_Net_Loss_Per

Basic and Diluted Net Loss Per Common Share	3 Months Ended
	Mar. 31, 2015
Basic and Diluted Net Loss Per Common Share
Basic and Diluted Net Loss Per Common Share
	9. Basic and Diluted Net Loss Per Common Share
	Basic net loss per common share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period, excluding the effects of options and restricted stock units outstanding. Diluted net loss per common share is computed by dividing the net loss by the sum of the weighted average number of common shares outstanding during the period plus the potential dilutive effects of options and restricted stock units outstanding during the period calculated in accordance with the treasury stock method. Because the impact of these items is anti-dilutive during periods of net loss, there was no difference between weighted average number of shares used to calculate basic and diluted net loss per common share for the three months ended March 31, 2015 and 2014.
	The calculation of weighted average diluted shares outstanding excludes the dilutive effect of options and restricted stock units outstanding, as the impact of such items are anti-dilutive during periods of net loss.  Shares excluded from the calculation, prior to the use of the treasury stock method, unweighted, were 4.0 million and 2.7 million at March 31, 2015 and 2014, respectively.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events
Subsequent Events
	10. Subsequent Events
	On April 1, 2015, the Company repaid the outstanding balance of the credit facility. The total payoff was $5.8 million, which included accrued interest of $824 thousand and prepayment and other additional fees of $51 thousand. The Company wrote-off to interest expense $311 thousand of unamortized debt issuance costs as of the date of payoff.
	On April 29, 2015 the U.S. Food and Drug Administration (“FDA”) approved KYBELLA™, also known as ATX-101 in territories outside the U.S., for improvement in the appearance of moderate to severe convexity or fullness associated with submental fat in adults. As a result, the Company incurred a milestone of $500 thousand due to LA Biomed.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2015
Summary of Significant Accounting Policies and Basis of Presentation
Reclassifications
	Reclassifications
	Certain prior year amounts have been reclassified to conform to the current year presentation.
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 reported amounts in the financial statements and accompanying notes. Actual results could materially differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these condensed consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including: expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the financial statements.
Cash and Cash Equivalents and Marketable Securities
	Cash and Cash Equivalents and Marketable Securities
	All highly liquid securities with maturities of 90 days or less from the date of purchase are considered to be cash equivalents. As of March 31, 2015 and December 31, 2014, cash and cash equivalents were comprised of funds invested in cash and money market accounts. The Company maintains cash balances in excess of amounts insured by the Federal Deposit Insurance Corporation, “FDIC”. The accounts are monitored by management to mitigate the risk.
	Investments with maturities of more than 90 days from the date of purchase are classified as marketable securities. Marketable securities are stated at fair value. The Company has classified its entire marketable securities portfolio as available-for-sale securities. Accordingly, any unrealized gain or loss on the investments is reported as a component of accumulated other comprehensive income (loss). The amortized cost of these securities is adjusted for amortization of premiums and accretion of discounts to maturity, as applicable. Such amortizations and accretions are included as a component of interest income. The entire marketable securities portfolio is considered available for use in current operations and, accordingly, all such investments are considered current assets although the stated maturity of individual investments may be more than one year beyond the balance sheet date.
	Realized gains and losses, determined on a specific identification basis, and declines in value, if any, judged to be other-than-temporary on available-for-sale securities are reported as a component of interest income. When securities are sold, any associated unrealized gain or loss previously reported in accumulated other comprehensive income (loss) is reclassified out of stockholders’ equity and recorded in the statement of operations and comprehensive loss for the period. Accrued interest and dividends are included in interest income.
	On a quarterly basis, the Company reviews the available-for-sale securities for other-than-temporary declines in fair value below the amortized cost basis. This evaluation is based on a number of factors including the length of time and extent to which the fair value has been below the cost basis and any adverse conditions related specifically to the security, including any changes to the credit rating of the security. If the Company concludes that an other-than-temporary impairment exists, it recognizes an impairment charge to reduce the investment to fair value and records the related charge as a reduction of interest income. No impairment charges were recognized for the three months ended March 31, 2015 and 2014.
Property and Equipment
	Property and Equipment
	Property and equipment are recorded at historical cost and consisted of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Cameras	$	923		$	923
	Computer hardware and electronics	475			420
	Furniture and fixtures	345			345
	Software	41			9
	Leasehold improvements	1,465			1,465
	Construction in process	181			—
		3,430			3,162
	Less accumulated depreciation	(1,488		)	(1,315		)
		$	1,942		$	1,847
	Except for leasehold improvements, depreciation is recorded using the straight-line method over the estimated useful lives of the assets (one to five years). Leasehold improvements are being depreciated on a straight line basis over the three year lease term, which is the shorter of the improvements expected useful lives and the lease term.
	The Company reviews its property and equipment assets for impairment in value whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company had no impairments or disposals during the three months ended March 31, 2015 and 2014.
Concentration of Credit Risk
	Concentration of Credit Risk
	Financial instruments, which potentially subject the Company to significant concentrations of credit risk, consist primarily of cash and cash equivalents and marketable securities. The primary objectives for the Company’s investment portfolio are the preservation of capital and the maintenance of liquidity. The Company does not enter into any investment transactions for trading or speculative purposes.
	The Company’s investment policy limits investments to certain types of instruments such as certificates of deposit, money market instruments, obligations issued by U.S. government and U.S. government agencies and corporate debt securities and places restrictions on maturities and concentration by type and issuer. The Company maintains cash balances in excess of amounts insured by the FDIC. The accounts are monitored by management to mitigate the risk.
Comprehensive Income (Loss)
	Comprehensive Income (Loss)
	Comprehensive income (loss) is comprised of net loss and other comprehensive income (loss). For the three months ended March 31, 2015 and 2014, the only component of other comprehensive income (loss) is net unrealized gains on marketable securities. There were no material reclassifications out of accumulated other comprehensive income (loss) during the three months ended March 31, 2015 and 2014.
Recent Accounting Pronouncements
	Recent Accounting Pronouncements
	In May 2014, a new standard was issued related to revenue recognition, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The new standard will replace most of the existing revenue recognition standards in U.S. GAAP when it becomes effective on January 1, 2017. The FASB voted on April 1, 2015 to propose a deferral of the effective date of the new revenue standard by one year, but to permit entities to adopt one year earlier if they choose (i.e., the original effective date). For U.S. GAAP public entities, the proposed deferral would result in the new revenue standard being effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2017. Calendar year-end public entities would therefore be required to apply the new revenue guidance beginning in their 2018 interim and annual financial statements. The new standard allows for either “full retrospective” adoption, whereby the new standard is applied to each prior reporting period presented or “modified retrospective” adoption, whereby the new standard is only applied to the most current period presented with the cumulative effect of the change recognized at the date of the initial application. The Company is assessing the potential impact of the new standard on its consolidated statements of financial position and results of operations and comprehensive income (loss) and has not yet selected a transition method.
	In August 2014, a new standard was issued which will require management to evaluate if there is substantial doubt about the entity’s ability to continue as a going concern and, if so, disclose it in both annual and interim reporting periods. The new standard will become effective for the Company’s annual filing for the period ending December 31, 2016 and interim periods thereafter, with early adoption permitted. The Company does not believe the adoption of this accounting standard will have a material impact on the Company’s consolidated financial statements and related disclosures.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2015
Summary of Significant Accounting Policies and Basis of Presentation
Schedule of property and equipment recorded at historical cost
	Property and equipment are recorded at historical cost and consisted of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Cameras	$	923		$	923
	Computer hardware and electronics	475			420
	Furniture and fixtures	345			345
	Software	41			9
	Leasehold improvements	1,465			1,465
	Construction in process	181			—
		3,430			3,162
	Less accumulated depreciation	(1,488		)	(1,315		)
		$	1,942		$	1,847

Marketable_Securities_Tables

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Marketable Securities
Schedule of marketable securities held
	The Company’s marketable securities held as of March 31, 2015 and December 31, 2014 are summarized below (in thousands):
	Type of security as of March 31, 2015	Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
	Corporate debt securities:
	Financial	$	17,969	$	—	$	(6	)	$	17,963
	Industrial	10,048		1		(5		)	10,044
	Other	17,796		1		(6		)	17,791
	Total available-for-sale securities	$	45,813	$	2	$	(17	)	$	45,798
	Type of security as of December 31, 2014	Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair
				Gains		Losses			Value
	U.S. government agency securities	$	2,000	$	1	$	—		$	2,001
	Corporate debt securities:
	Financial	28,067		—		(19		)	28,048
	Industrial	20,625		1		(14		)	20,612
	Other	19,796		—		(22		)	19,774
	Total available-for-sale securities	$	70,488	$	2	$	(55	)	$	70,435
Schedule of maturities of the entity's marketable securities available for sale
	The maturities of the Company’s marketable securities are as follows (in thousands):
		March 31, 2015				December 31, 2014
		Amortized		Estimated Fair		Amortized			Estimated Fair
		Cost		Value		Cost			Value
	Mature in one year or less	$	45,514	$	45,499	$	66,863		$	66,816
	Mature after one year through two years	299		299		3,625			3,619
		$	45,813	$	45,798	$	70,488		$	70,435

Notes_Payable_Tables

Notes Payable (Tables)	3 Months Ended
	Mar. 31, 2015
Notes Payable
Schedule of notes payable
	Notes payable consisted of the following (in thousands):
		March 31,			December 31,
		2015			2014
	Note payable to Bayer	$	24,396		$	22,166
	Notes payable related to credit facility	4,518			5,979
		28,914			28,145
	Less current portion	(4,518		)	(5,484		)
	Notes payable-net of current portion	$	24,396		$	22,661

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity
Schedule of shares of the Company's common stock reserved for future issuance
	Shares of the Company’s common stock reserved for future issuance are as follows (in thousands):
		March 31,
		2015
	Common stock awards outstanding	4,018
	Common stock awards available for grant	929
	Total common shares reserved for future issuance	4,947
Summary of stock option activity
		Number of		Weighted-
		Options		Average
		(in thousands)		Exercise Price
	Outstanding at December 31, 2014	2,975		$	23.59
	Granted	1,013		38.87
	Exercised	(101	)	9.06
	Cancelled	(10	)	29.47
	Outstanding at March 31, 2015	3,877		$	27.93
Summary of restricted stock unit activity
		Number of		Weighted-
		RSUs		Average
		(in thousands)		Grant-Date
				Fair Value
	Outstanding at December 31, 2014	138		$	37.92
	Granted	16		45.08
	Vested	(12	)	22.49
	Cancelled	(1	)	44.02
	Outstanding at March 31, 2015	141		$	40.06
Schedule of equity-based compensation cost recorded in the statements of operations and comprehensive loss
	Total equity-based compensation cost recorded in the condensed consolidated statements of operations and comprehensive loss, which includes the value of stock options and RSUs is allocated as follows (in thousands):
		Three Months Ended
		March 31,
		2015			2014
	Research and development	$	2,048		$	1,488
	Selling, general and administrative	2,384			1,423
		$	4,432		$	2,911

Collaborations_Licensing_and_C1

Collaborations, Licensing and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2015
Collaborations, Licensing and Contingencies
Schedule of acquisition date costs allocated to the acquired rights
	The acquisition date costs allocated to the acquired rights consists of the following (in thousands):
	Fair value of common stock issued	$	31,429
	Fair value of note payable to Bayer	21,600
	Other	(272		)
	Total in-process research and development	$	52,757

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Measurements
Schedule of fair value hierarchy about each major category of financial assets and liabilities measured at fair value on a recurring basis
	The following fair value hierarchy table presents information about each major category of the Company’s financial assets measured at fair value on a recurring basis as of March 31, 2015 and December 31, 2014 (in thousands).
		Fair Value Measurement at March 31, 2015 Using:
		Quoted Prices		Significant		Significant		Balance as of
		in Active		Other		Unobservable		March 31, 2015
		Markets for		Observable		Inputs
		Identical		Inputs		(Level 3)
		Assets		(Level 2)
		(Level 1)
	Assets:
	Cash equivalents	$	154,959	$	—	$	—	$	154,959
	Corporate debt securities	—		45,798		—		45,798
	Total	$	154,959	$	45,798	$	—	$	200,757
		Fair Value Measurement at December 31, 2014 Using:
		Quoted Prices		Significant		Significant		Balance as of
		in Active		Other		Unobservable		December 31,
		Markets for		Observable		Inputs		2014
		Identical		Inputs		(Level 3)
		Assets		(Level 2)
		(Level 1)
	Assets:
	Cash equivalents	$	22,691	$	—	$	—	$	22,691
	U.S. government agency securities	—		2,001		—		2,001
	Corporate debt securities	—		68,434		—		68,434
	Total	$	22,691	$	70,435	$	—	$	93,126

Organization_Details

Organization (Details) (USD $)	3 Months Ended	1 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Organization and Basis of Presentation
Common stock, par value (in dollars per share)	$0.00	$0.00	$0.00
Net proceeds, after deducting the underwriting discounts and offering transaction costs	$134,973
Underwritten Public Offering
Organization and Basis of Presentation
Common stock issued (in shares)		2,600
Common stock, par value (in dollars per share)	$0.00	$0.00
Offer price of common stock (in dollars per share)	$48	$48
Net proceeds, after deducting the underwriting discounts and offering transaction costs		$134,700
Underwriters Option to Purchase Additional Shares
Organization and Basis of Presentation
Common stock issued (in shares)		391

Summary_of_Significant_Account3

Summary of Significant Accounting Policies and Basis of Presentation (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Cash, Cash Equivalents and Marketable Securities
Impairment charge	$0	$0
Property and Equipment
Gross	3,430		3,162
Less accumulated depreciation	-1,488		-1,315
Net	1,942		1,847
Disposal of property and equipment	0	0
Impairment of property and equipment	0	0
Minimum
Property and Equipment
Estimated useful lives	1 year
Maximum
Property and Equipment
Estimated useful lives	5 years
Cameras
Property and Equipment
Gross	923		923
Computer hardware and electronics
Property and Equipment
Gross	475		420
Furniture and fixtures
Property and Equipment
Gross	345		345
Software
Property and Equipment
Gross	41		9
Leasehold improvements
Property and Equipment
Gross	1,465		1,465
Estimated useful lives	3 years
Construction in process
Property and Equipment
Gross	$181

Summary_of_Significant_Account4

Summary of Significant Accounting Policies and Basis of Presentation (Details 2) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Comprehensive Income (Loss)
Reclassifications out of accumulated other comprehensive income related to marketable securities	$0	$0

Marketable_Securities_Details

Marketable Securities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Marketable securities
Amortized Cost	$45,813	$70,488
Gross Unrealized Gains	2	2
Gross Unrealized Losses	-17	-55
Estimated Fair Value	45,798	70,435
Amortized Cost
Mature in one year or less	45,514	66,863
Mature after one year through two years	299	3,625
Amortized cost	45,813	70,488
Estimated Fair Value
Mature in one year or less	45,499	66,816
Mature after one year through two years	299	3,619
Estimated Fair Value	45,798	70,435
U.S. government agency securities
Marketable securities
Amortized Cost		2,000
Gross Unrealized Gains		1
Estimated Fair Value		2,001
Estimated Fair Value
Estimated Fair Value		2,001
Financial
Marketable securities
Amortized Cost	17,969	28,067
Gross Unrealized Losses	-6	-19
Estimated Fair Value	17,963	28,048
Estimated Fair Value
Estimated Fair Value	17,963	28,048
Industrial
Marketable securities
Amortized Cost	10,048	20,625
Gross Unrealized Gains	1	1
Gross Unrealized Losses	-5	-14
Estimated Fair Value	10,044	20,612
Estimated Fair Value
Estimated Fair Value	10,044	20,612
Other
Marketable securities
Amortized Cost	17,796	19,796
Gross Unrealized Gains	1
Gross Unrealized Losses	-6	-22
Estimated Fair Value	17,791	19,774
Estimated Fair Value
Estimated Fair Value	$17,791	$19,774

Notes_Payable_Details

Notes Payable (Details) (USD $)	3 Months Ended		0 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Feb. 28, 2013	Jan. 31, 2013	Oct. 02, 2012	Nov. 30, 2012	Dec. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Mar. 21, 2011	Dec. 31, 2011
Notes Payable
Total	$28,914,000						$28,145,000	$28,914,000
Current portion	-4,518,000						-5,484,000	-4,518,000
Notes payable-net of current portion	24,396,000						22,661,000	24,396,000
Balance of the note payable
Accrued interest expense	998,000						2,857,000	998,000
Amount outstanding under credit facility	15,000,000						15,000,000	15,000,000
Remaining borrowing capacity	0							0
Amortization of debt discount and issuance cost	275,000	130,000
Series C Redeemable Convertible Preferred Stock Warrants
Balance of the note payable
Warrants issued (in shares)										34,000
Exercise price (in dollars per unit)										13.353
Series D Redeemable Convertible Preferred Stock Warrants
Balance of the note payable
Warrants issued (in shares)											86,000
Exercise price (in dollars per unit)											13.904
Note Payable Related to Credit Facility
Notes Payable
Total	4,518,000						5,979,000	4,518,000
Balance of the note payable
Interest expense related to the notes payable	169,000						356,000
Accrued interest expense	824,000						768,000	824,000
Maximum borrowing capacity										15,000,000
Initial period of interest only payments	6 months
Fixed rate of interest in initial period (as a percent)	11.50%
Period of payment of interest and principal following the initial period	30 months
Fixed rate of interest in period following initial period (as a percent)	8.50%
Final payment percentage	6.00%
Amount drawn under credit facility			5,000,000	5,000,000	5,000,000
Amount that the entity can draw, pursuant to the extension obtained						10,000,000
Amortization of debt discount and issuance cost		85,000
Unamortized debt issuance cost	-311,000						-396,000	-311,000
Note Payable to Bayer
Notes Payable
Total	24,396,000						22,166,000	24,396,000
Face amount of debt issued		51,000,000							51,000,000
Interest rate (as a percent)		5.00%							5.00%
Option to pay accrued interest in cash (as a percent)									80.00%
Interest paid								510,000
Deferred interest								2,000,000
Term of debt									10 years
Fair value of note		21,600,000							21,600,000
Assumed borrowing rate (as a percent)									15.00%
Balance of the note payable
Face value of note payable to Bayer		51,000,000							51,000,000
Amortization of debt discount	190,000	45,000
Interest expense related to the notes payable	635,000	168,000
Accrued interest expense	174,000						2,100,000	174,000
Remaining unamortized discount	$28,600,000						$28,800,000	$28,600,000

Stockholders_Equity_Details

Stockholders' Equity (Details)	1 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Mar. 31, 2015
Common Stock Reserved for Future Issuance
Common stock awards outstanding (in shares)		4,018
Common stock awards available for grant (in shares)		929
Total common shares reserved for future issuance		4,947
Employee Stock Purchase Plan
Common Stock Reserved for Future Issuance
Shares reserved for issuance	682
Offering period	6 months
Exercise price of shares on common stock (as a percent)	85.00%

Stockholders_Equity_Details_2

Stockholders' Equity (Details 2)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Incentive stock options | Individuals owning more than 10% | Minimum
Stock Awards
Voting power of all classes of stock (as a percent)	10.00%
Incentive stock options | Individuals owning more than 10% | Maximum
Stock Awards
Expiration period	5 years
Incentive stock options | 10% Stockholder
Stock Awards
Voting power of all classes of stock (as a percent)	10.00%
Incentive stock options | 10% Stockholder | Minimum
Stock Awards
Minimum exercise price as a percentage of fair market value (as a percent)	110.00%
Stock options
Stock Awards
Expiration period	10 years
Stock options | Employees
Stock Awards
Vesting period	4 years
2012 Equity Incentive Award
Stock Awards
Threshold number of annual additional shares of common stock available for issuance	1,512,687
Percentage for the threshold number of annual additional shares of common stock available for issuance, expressed as percentage of common stock issued and outstanding on last day of the preceding calendar year	4.00%
Number of shares authorized for grant	5,000,000	4,100,000
2014 Plan
Stock Awards
Number of shares authorized for grant	900,000

Stockholders_Equity_Details_3

Stockholders' Equity (Details 3) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015
Number of Shares
Outstanding at the end of the period (in shares)	4,018
Stock options
Number of Shares
Outstanding at the beginning of the period (in shares)	2,975
Granted (in shares)	1,013
Exercised (in shares)	-101
Forfeited (in shares)	-10
Outstanding at the end of the period (in shares)	3,877
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$23.59
Granted (in dollars per share)	$38.87
Exercised (in dollars per share)	$9.06
Forfeited (in dollars per share)	$29.47
Outstanding at the end of the period (in dollars per share)	$27.93
Restricted stock units
Number of Shares
Outstanding at the beginning of the period (in shares)	138
Granted (in shares)	16
Vested (in shares)	-12
Cancelled (in shares)	-1
Outstanding at the end of the period (in shares)	141
Weighted-Average Grant-Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$37.92
Granted (in dollars per share)	$45.08
Vested (in dollars per share)	$22.49
Cancelled (in dollars per share)	$44.02
Outstanding at the end of the period (in dollars per share)	$40.06

Stockholders_Equity_Details_4

Stockholders' Equity (Details 4) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Stock-based compensation expense
Total equity-based compensation cost	$4,432,000	$2,911,000
Stock options
Stock-based compensation expense
Unrecognized compensation expense	45,600,000
Expected weighted-average period of recognition	3 years 2 months 23 days
Restricted stock units
Stock-based compensation expense
Unrecognized compensation expense	2,300,000
Expected weighted-average period of recognition	1 year 1 month 17 days
Research and development
Stock-based compensation expense
Total equity-based compensation cost	2,048,000	1,488,000
Selling, general and administrative
Stock-based compensation expense
Total equity-based compensation cost	$2,384,000	$1,423,000

Collaborations_Licensing_and_C2

Collaborations, Licensing and Contingencies (Details) (USD $)	3 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended	116 Months Ended	1 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2015	Aug. 31, 2005	Mar. 31, 2015	Feb. 28, 2015
Acquisition date costs allocated to the acquired rights
In-process research and development	$52,757,000
Note Payable to Bayer
Collaboration Arrangements
Notes issued as a part of consideration	51,000,000	51,000,000
Interest rate (as a percent)	5.00%	5.00%
Acquisition date costs allocated to the acquired rights
Assumed borrowing rate (as a percent)		15.00%
Bayer | Note Payable to Bayer
Collaboration Arrangements
Interest rate (as a percent)			5.00%		5.00%
Acquisition date costs allocated to the acquired rights
Assumed borrowing rate (as a percent)			15.00%
License agreement | Bayer | KYTHERA Holdings Ltd.
Collaboration Arrangements
Number of common stock issued as a part of consideration		698
Value of common stock issued as a part of consideration		33,000,000
Average closing stock price (in dollars per share)		$47.27
Notes issued as a part of consideration	51,000,000	51,000,000
Interest rate (as a percent)	5.00%	5.00%
Acquisition date costs allocated to the acquired rights
Fair value of common stock issued		31,429,000
Other		-272,000
In-process research and development		52,757,000
Share issue price (in dollars per share)	$45.02	$45.02
Deferred development funds	967,000	967,000
Amounts recognized as offsets to in process research and development expenses		695,000
License agreement | Bayer | KYTHERA Holdings Ltd. | Maximum
Collaboration Arrangements
Consideration upon the achievement of certain long-term sales milestone payments on annual sales	123,800,000	123,800,000
License agreement | Bayer | KYTHERA Holdings Ltd. | Note Payable to Bayer
Acquisition date costs allocated to the acquired rights
Fair value of note payable to Bayer		21,600,000
Fair value of note payable to Bayer	21,600,000	21,600,000
Assumed borrowing rate (as a percent)		15.00%
License agreement | Los Angeles Biomedical Research Institute
Acquisition date costs allocated to the acquired rights
Milestone payment				500,000
Non-royalty sublicense fees equal to a certain percentage of sublicense income (as a percent)				10.00%
Maximum non-royalty sublicense fees				5,000,000
Right to issue capital to satisfy payment of sublicense fees (as a percent)				50.00%
Non-royalty sublicense fee paid					3,600,000
License agreement | Actelion
Acquisition date costs allocated to the acquired rights
Initial payment			1,500,000
License agreement | Actelion | Maximum
Acquisition date costs allocated to the acquired rights
Potential milestone and royalty payments						25,500,000
License agreement | University of Pennsylvania
Acquisition date costs allocated to the acquired rights
Initial milestone payment						100,000
Initial term upon which payments will begin						3 years
License agreement | University of Pennsylvania | Maximum
Acquisition date costs allocated to the acquired rights
Potential milestone and royalty payments						$4,100,000

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	3 Months Ended	12 Months Ended	1 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Fair value of financial assets and liabilities measured at fair value on a recurring basis
Adjustment made to U.S. Treasury securities	$0	$0
Fair value assets, amount transferred between measurement levels	0		0
Fair value liabilities, amount transferred between measurement levels	0		0
Assets:
Marketable securities	45,798	70,435
Note Payable to Bayer
Fair value of financial assets and liabilities measured at fair value on a recurring basis
Interest rate (as a percent)			5.00%
Discount rate (as a percent)			15.00%
Note Payable to Bayer | Bayer
Fair value of financial assets and liabilities measured at fair value on a recurring basis
Interest rate (as a percent)	5.00%
Discount rate (as a percent)	15.00%
U.S. government agency securities and Corporate debt securities
Fair value of financial assets and liabilities measured at fair value on a recurring basis
Maximum maturity period	2 years
U.S. government agency securities
Assets:
Marketable securities		2,001
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	154,959	22,691
Total	154,959	22,691
Recurring basis | Significant Other Observable Inputs (Level 2)
Assets:
Total	45,798	70,435
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. government agency securities
Assets:
Marketable securities		2,001
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate debt securities:
Assets:
Marketable securities	45,798	68,434
Recurring basis | Total
Assets:
Cash equivalents	154,959	22,691
Total	200,757	93,126
Recurring basis | Total | U.S. government agency securities
Assets:
Marketable securities		2,001
Recurring basis | Total | Corporate debt securities:
Assets:
Marketable securities	$45,798	$68,434

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Taxes
Provision for income taxes	$0
Accrued interest and penalties associated with uncertain tax positions	0
Interest and penalties incurred associated with uncertain tax positions	$0	$0

Basic_and_Diluted_Net_Loss_Per1

Basic and Diluted Net Loss Per Common Share (Details)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Basic and Diluted Net Loss Per Common Share
Shares excluded from the calculation of net loss per common share, prior to the use of the treasury stock method, unweighted	4	2.7

Subsequent_Events_Details

Subsequent Events (Details) (Subsequent event, USD $)	0 Months Ended
	Apr. 01, 2015	Apr. 29, 2015
Note Payable Related to Credit Facility
Subsequent events
Total payoff	$5,800,000
Accrued interest paid as part of total payoff	824,000
Prepayment and other additional fees as part of total payoff	51,000
Unamortized debt issuance costs written off	311,000
License agreement | Los Angeles Biomedical Research Institute
Subsequent events
Milestone payment due		$500,000