CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Balances at Dec. 31, 2013	$ 41,249	$ 34	$ 337,639	$ (296,429)	$ 5
Balances (in shares) at Dec. 31, 2013		33,636,000
Increase (Decrease) in Stockholders' Equity
Follow-on public offering, net (in shares)		1,840,000
Follow-on public offering, net	110,407	2	110,405
Exercise of stock options (in shares)		511,000
Exercise of stock options	5,732		5,732
Cashless exercise of warrants (in shares)		35,000
Stock-based compensation	17,199		17,199
Net unrealized gain (loss) on investments	3				3
Net loss	(19,518)			(19,518)
Balances at Sep. 30, 2014	$ 155,072	$ 36	$ 470,975	$ (315,947)	$ 8
Balances (in shares) at Sep. 30, 2014		36,022,000