CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Series B Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Income	Noncontrolling Interest
Beginning Balances at Dec. 31, 2015	$ 14,190		$ 11	$ 396,407	$ (6,487)	$ (377,814)	$ 2,229	$ (156)
Beginning Balances (in shares) at Dec. 31, 2015			10,747
Net loss	(13,703)					(13,695)		(8)
Other comprehensive loss	(192)						(176)	(16)
Issuance of warrants	569			569
Issuance of common stock in connection with vesting of stock awards (shares)			471
Stock-based compensation	3,290			3,290
Shares withheld in payment of taxes in connection with net share settlement of restricted stock units	(221)				(221)
Shares withheld in payment of taxes in connection with net share settlement of restricted stock units (shares)			(109)
Ending Balances at Dec. 31, 2016	3,933		$ 11	400,266	(6,708)	(391,509)	2,053	(180)
Ending Balances (in shares) at Dec. 31, 2016			11,109
Net loss	(8,152)					(8,138)		(14)
Other comprehensive loss	638						622	16
Issuance of Series B convertible preferred stock, net of issuance cost	11,878	$ 3		11,875
Issuance of Series B convertible preferred stock, net of issuance cost (shares)		3,000
Issuance of common stock in connection with public offering	12,560		$ 3	12,557
Issuance of common stock in connection with public offering (shares)			2,845
Issuance of warrants	2,319			2,319
Issuance of common stock in connection with vesting of stock awards	1		$ 1
Issuance of common stock in connection with vesting of stock awards (shares)			604
Stock-based compensation	2,480			2,480
Shares withheld in payment of taxes in connection with net share settlement of restricted stock units	(777)				(777)
Shares withheld in payment of taxes in connection with net share settlement of restricted stock units (shares)			(178)
Issuance of shares to non-employees	255			255
Issuance of shares to non-employees (shares)			56
Cancellation of reacquired warrants from extinguishment of debt	(1,282)			(1,282)
Ending Balances at Dec. 31, 2017	$ 23,853	$ 3	$ 15	$ 428,470	$ (7,485)	$ (399,647)	$ 2,675	$ (178)
Ending Balances (in shares) at Dec. 31, 2017		3,000	14,436