Summary of Significant Accounting Policies (Details 3) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue Recognition
Period for which company is having option of accepting returns from customers									60 days
Deferred product revenue	$ 786								$ 786
Cost of product	219								219
Research and Development Expenses
Payments to Antibiotics for facility improvements, manufacturing equipment and raw materials									2,258
Difference in basic and dilutive loss per share (in dollars per share)									$ 0
Numerator:
Net income (loss)	$ (9,517)	$ (7,745)	$ (7,948)	$ 28,840	$ (9,603)	$ (9,560)	$ (9,982)	$ (9,640)	$ 3,630	$ (38,785)	$ (38,803)
Denominator:
Weighted average number of common shares outstanding									34,217,298	31,257,376	26,773,755
Effect of dilutive securities:
Stock options (in shares)									62,481
Dilutive potential common shares									62,481
Shares used in calculating diluted earnings per share									34,279,779	31,257,376	26,773,755
Antidilutive securities
Antidilutive common stock excluded from the calculation of dilutive shares									5,583,128	3,862,771	3,250,165
Options
Antidilutive securities
Antidilutive common stock excluded from the calculation of dilutive shares									5,579,042	3,858,685	3,246,079
Warrants
Antidilutive securities
Antidilutive common stock excluded from the calculation of dilutive shares									4,086	4,086	4,086