Consolidated Statements of Changes in Stockholder's Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Series A Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2010	$ (44,320)	$ 49	$ 2	$ 49,415		$ (93,786)
Balance (in shares) at Dec. 31, 2010		49,000,000	1,592,762
Increase (Decrease) in Stockholders' Equity
Exercise of stock options	29			29
Exercise of stock options (in shares)			69,559
Share-based compensation	(82)			(82)
Net (loss) income	53,815					53,815
Other comprehensive income (loss)	1				1
Balance at Dec. 31, 2011	9,443	49	2	49,362	1	(39,971)
Balance (in shares) at Dec. 31, 2011		49,000,000	1,662,321
Increase (Decrease) in Stockholders' Equity
Share-based compensation	443			443
Issuance of employee stock purchase plan shares	223			223
Issuance of employee stock purchase plan shares (in shares)			36,727
Exercise of stock options	265			265
Exercise of stock options (in shares)			159,264
Warrant Exercise	1,156			1,156
Warrant Exercise (in shares)			64,309
Issuance of common stock, net of underwriters' discount and offering costs	92,382		17	92,365
Issuance of common stock, net of underwriters' discount and offering costs (in shares)			16,449,250
Conversion of preferred stock to common stock		(49)	12	37
Conversion of preferred stock to common stock to common stock (in shares)		(49,000,000)	12,249,998
Net (loss) income	(46,284)					(46,284)
Other comprehensive income (loss)	(58)				(58)
Balance at Dec. 31, 2012	57,570		31	143,851	(57)	(86,255)
Balance (in shares) at Dec. 31, 2012			30,621,869
Increase (Decrease) in Stockholders' Equity
Exercise of over allotment from secondary offering	1,791			1,791
Exercise of over allotment from secondary offering (in shares)			239,432
Share-based compensation	1,913			1,913
Issuance of employee stock purchase plan shares	444			444
Issuance of employee stock purchase plan shares (in shares)			81,370
Exercise of stock options	78			78
Exercise of stock options (in shares)			62,513
Equity conversion feature on issuance of convertible notes, less issuance costs of $869	21,467			21,467
Equity issued on conversion of convertible notes	42,417		9	42,408
Equity issued on conversion of convertible notes (in shares)			8,978,253
Net (loss) income	(92,273)					(92,273)
Other comprehensive income (loss)	57				57
Balance at Dec. 31, 2013	$ 33,464		$ 40	$ 211,952		$ (178,528)
Balance (in shares) at Dec. 31, 2013			39,983,437