CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2013	$ 72,519	$ 23	$ 314,405	$ (1,380)	$ (240,529)
Balance (in shares) at Dec. 31, 2013		23,125,565		112,350
Stock based compensation	3,784	$ 0	3,784	$ 0	0
Issuance of shares of common stock for the cashless exercise of stock options	0	$ 0	0	$ 0	0
Issuance of shares of common stock for the cashless exercise of stock options (in shares)		72,910		0
Exercise of stock options to purchase common stock for cash	147	$ 0	147	$ 0	0
Exercise of stock options to purchase common stock for cash (in shares)		23,334		0
Issuance shares of common stock for the cashless exercise of Series A Warrants	0	$ 1	(1)	$ 0	0
Issuance shares of common stock for the cashless exercise of Series A Warrants (in shares)		836,961		0
Issuance shares of common stock for the cashless exercise of Series B Warrants	0	$ 0	0	$ 0	0
Issuance shares of common stock for the cashless exercise of Series B Warrants (in shares)		329,753		0
Proceeds from a shareholder transaction	102	$ 0	102	$ 0
Net loss	(32,535)	0	0	0	(32,535)
Balance at Dec. 31, 2014	44,017	$ 24	318,437	$ (1,380)	(273,064)
Balance (in shares) at Dec. 31, 2014		24,388,523		112,350
Stock based compensation	3,742	$ 0	3,742	$ 0	0
Issuance of shares of common stock for the cashless exercise of stock options	0	$ 0	0	$ 0	0
Issuance of shares of common stock for the cashless exercise of stock options (in shares)		4,845		0
Exercise of stock options to purchase common stock for cash	0	$ 0	0	$ 0	0
Exercise of stock options to purchase common stock for cash (in shares)		37,093		0
Net loss	(29,192)	$ 0	0	$ 0	(29,192)
Balance at Dec. 31, 2015	18,567	$ 24	322,179	$ (1,380)	(302,256)
Balance (in shares) at Dec. 31, 2015		24,430,461		112,350
Stock based compensation	1,928	$ 0	1,928	$ 0	0
Exercise of stock options to purchase common stock for cash	0	$ 0	0	$ 0	0
Exercise of stock options to purchase common stock for cash (in shares)		1,333		0
Issuance of common stock at a weighted average share price of net of offering costs	2,876	$ 2	2,874	$ 0	0
Issuance of common stock at a weighted average share price of net of offering costs (in shares)		1,506,808		0
Net loss	(17,273)	$ 0	0	$ 0	(17,273)
Balance at Dec. 31, 2016	$ 6,098	$ 26	$ 326,981	$ (1,380)	$ (319,529)
Balance (in shares) at Dec. 31, 2016		25,938,602		112,350