Consolidated Statements of Stockholders' Deficit (USD $) In Thousands, except Share data	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit	Total
Beginning balances at Dec. 31, 2010		$ 67	$ 798,840	$ 1	$ (954,183)	$ (155,275)
Beginning balances, shares at Dec. 31, 2010		66,986,940
Stock options exercised			1,130			1,130
Stock options exercised, shares		257,435
Compensation expense on share-based awards			4,100			4,100
Net proceeds from sale of shares		13	107,020			107,033
Net proceeds from sale of shares, shares		12,687,065
Conversion of 5.75% convertible notes		6	33,254			33,260
Conversion of 5.75% convertible notes, shares		6,149,727
Other comprehensive income (loss)				(97)		(97)
Net loss					(36,267)	(36,267)
Ending balances at Dec. 31, 2011		86	944,344	(96)	(990,450)	(46,116)
Ending balances, shares at Dec. 31, 2011		86,081,167
Stock options exercised		1	2,407			2,408
Stock options exercised, shares		481,058
Shares issued for services rendered			149			149
Shares issued for services rendered, shares		171,271
Compensation expense on share-based awards			7,298			7,298
Net proceeds from sale of shares			254			254
Net proceeds from sale of shares, shares		45,553
Other comprehensive income (loss)				101		101
Net loss					(18,735)	(18,735)
Ending balances at Dec. 31, 2012		87	954,452	5	(1,009,185)	(54,641)
Ending balances, shares at Dec. 31, 2012		86,779,049
Stock options exercised		3	14,528			14,531
Stock options exercised, shares		2,521,764				(2,522,000)
Restricted stock vesting		0	339			339
Restricted stock vesting, shares		211,389
Compensation expense on share-based awards			8,480			8,480
Excess tax benefit from stock options			178			178
Stock issued in connection with the Takeda Termination and Transition agreement		6	55,397			55,403
Stock issued in connection with the Takeda Termination and Transition agreement, shares		6,128,641
Net proceeds from sale of shares		7	94,046			94,053
Net proceeds from sale of shares, shares		6,972,937
Other comprehensive income (loss)				51		51
Net loss					(13,504)	(13,504)
Ending balances at Dec. 31, 2013		$ 103	$ 1,127,420	$ 56	$ (1,022,689)	$ 104,890
Ending balances, shares at Dec. 31, 2013		102,613,780