CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Accumulated other Comprehensive Income (loss)	Accumulated Deficit
Balance at Dec. 31, 2010	$ 23,676	$ 269	$ 230,299	$ (15)	$ (206,877)
Balance (in shares) at Dec. 31, 2010		26,895,389
Increase (decrease) in stockholders' equity
Exercise of common stock options	74		74
Exercise of common stock options (in shares)		21,851
Non-cash stock-based compensation expense	4,633		4,633
Issuance of common stock for 401k match	529	1	528
Issuance of common stock for 401k match (in shares)	68,558	68,558
Issuance of common stock upon public offering, net of offering costs of $2,360	49,333	71	49,262
Issuance of common stock upon public offering, net of offering costs of $2,360 (in shares)		7,130,000
Change in unrealized gain (loss) on investments	20			20
Effect of foreign currency translation	(17)			(17)
Net income (loss)	(38,785)				(38,785)
Balance at Dec. 31, 2011	39,463	341	284,796	(12)	(245,662)
Balance (in shares) at Dec. 31, 2011		34,115,798
Increase (decrease) in stockholders' equity
Exercise of common stock options	19		19
Exercise of common stock options (in shares)		11,436
Non-cash stock-based compensation expense	3,807		3,807
Issuance of common stock for 401k match	430	2	428
Issuance of common stock for 401k match (in shares)	179,336	179,336
Change in unrealized gain (loss) on investments	(3)			(3)
Effect of foreign currency translation	(6)			(6)
Net income (loss)	3,630				3,630
Balance at Dec. 31, 2012	47,340	343	289,050	(21)	(242,032)
Balance (in shares) at Dec. 31, 2012	34,306,570	34,306,570
Increase (decrease) in stockholders' equity
Exercise of common stock options	14		14
Exercise of common stock options (in shares)		7,550
Non-cash stock-based compensation expense	3,193		3,193
Issuance of common stock for 401k match	407	3	404
Issuance of common stock for 401k match (in shares)	267,329	267,329
Change in unrealized gain (loss) on investments	(12)			(12)
Effect of foreign currency translation	(38)			(38)
Net income (loss)	(30,506)				(30,506)
Balance at Dec. 31, 2013	$ 20,398	$ 346	$ 292,661	$ (71)	$ (272,538)
Balance (in shares) at Dec. 31, 2013	34,581,449	34,581,449