CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (shares) at Dec. 31, 2013		21,772,571
Beginning balance at Dec. 31, 2013	$ 172,408	$ 218	$ 641,941	$ (3,491)	$ (466,260)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity component of Convertible Notes, net of issuance costs	36,907		36,907
Purchase of convertible bond hedges, net of tax	(39,760)		(39,760)
Sale of warrants	25,620		25,620
Net shares issued in connection with the acquisition of Lumara Health (shares)		3,209,971
Net shares issued in connection with the acquisition of Lumara Health	111,964	$ 32	111,932
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units (shares)		617,008
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units	8,498	$ 6	8,492
Non-cash equity-based compensation	8,625		8,625
Unrealized gains (losses) on securities, net of tax	(126)			(126)
Net income (loss)	135,817				135,817
Ending balance (shares) at Dec. 31, 2014		25,599,550
Ending balance at Dec. 31, 2014	459,953	$ 256	793,757	(3,617)	(330,443)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued in connection with financings, net of issuance costs of $24.7 million (shares)		8,196,362
Shares issued in connection with financings, net of issuance costs of $24.7 million	407,477	$ 82	407,395
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units (shares)		937,205
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units	15,406	$ 9	15,397
Non-cash equity-based compensation	17,237		17,237
Unrealized gains (losses) on securities, net of tax	(588)			(588)
Net income (loss)	32,779				32,779
Ending balance (shares) at Dec. 31, 2015		34,733,117
Ending balance at Dec. 31, 2015	932,264	$ 347	1,233,786	(4,205)	(297,664)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units (shares)		355,450
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units	230	$ 3	227
Repurchase of common stock pursuant to the 2016 Share Repurchase Program (shares)		(831,744)
Repurchase of common stock pursuant to the 2016 Share Repurchase Program	(20,000)	$ (8)	(19,992)
Issuance of common stock under employee stock purchase plan (shares)		79,324
Issuance of common stock under employee stock purchase plan	1,468	$ 1	1,467
Non-cash equity-based compensation	22,543		22,543
Unrealized gains (losses) on securities, net of tax	367			367
Net income (loss)	(2,483)				(2,483)
Ending balance (shares) at Dec. 31, 2016		34,336,147
Ending balance at Dec. 31, 2016	$ 934,389	$ 343	$ 1,238,031	$ (3,838)	$ (300,147)