CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Total
Balance at Dec. 31, 2012	$ 215	$ 632,487	$ (3,247)	$ (456,658)	$ 172,797
Balance (in shares) at Dec. 31, 2012	21,507
Increase (Decrease) in Stockholders' Equity
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units	$ 3	1,274			1,277
Net shares issued in connection with the exercise of stock options and restricted stock units (in shares)	252
Shares issued in connection with employee stock purchase plan		176			176
Shares issued in connection with employee stock purchase plan (in shares)	14
Non-cash equity-based compensation		8,004			8,004
Unrealized losses on securities, net of tax			(244)		(244)
Net income (loss)				(9,602)	(9,602)
Balance at Dec. 31, 2013	$ 218	641,941	(3,491)	(466,260)	172,408
Balance (in shares) at Dec. 31, 2013	21,773
Increase (Decrease) in Stockholders' Equity
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	$ 32	111,932			111,964
Net shares issued in connection with acquisition (in shares)	3,210
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units	$ 6	8,492			8,498
Net shares issued in connection with the exercise of stock options and restricted stock units (in shares)	617
Non-cash equity-based compensation		8,625			8,625
Unrealized losses on securities, net of tax			(126)		(126)
Net income (loss)				135,817	135,817
Balance at Dec. 31, 2014	$ 256	793,757	(3,617)	(330,443)	459,953
Balance (in shares) at Dec. 31, 2014	25,600
Increase (Decrease) in Stockholders' Equity
Shares issued in connection with financings, net of issuance costs of $24.7 million	$ 82	407,395			407,477
Shares issued in connection with financings, net of issuance costs of $24.7 million (in shares)	8,196
Net shares issued in connection with the exercise of stock options and vesting of restricted stock units	$ 9	15,397			15,406
Net shares issued in connection with the exercise of stock options and restricted stock units (in shares)	937
Non-cash equity-based compensation		17,237			17,237
Unrealized losses on securities, net of tax			(588)		(588)
Net income (loss)				32,779	32,779
Balance at Dec. 31, 2015	$ 347	$ 1,233,786	$ (4,205)	$ (297,664)	$ 932,264
Balance (in shares) at Dec. 31, 2015	34,733