CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Common Stock [Member]		Additional Paid-In Capital [Member]	[1]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Total
Balances at Dec. 31, 2015		$ 2	[1]	$ 265,327		$ (5,167)	$ (2,302)	$ (186,514)	$ 71,346	[1]
Balances (in shares) at Dec. 31, 2015	[1]	18,286,961
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		$ 0	[1]	0		0	0	(15,956)	(15,956)	[1]
Other comprehensive income (loss)		0	[1]	0		0	(27)	0	(27)	[1]
Stock-based compensation expense		0	[1]	1,987		0	0	0	1,987	[1]
Issuance of common stock upon exercise of stock options for cash and releases of RSUs		$ 0	[1]	1		0	0	0	1	[1]
Issuance of common stock upon exercise of stock options for cash and releases of RSUs (in shares)	[1]	270,317
Issuance of common stock under employee stock purchase plan		$ 0	[1]	85		0	0	0	85	[1]
Issuance of common stock under employee stock purchase plan (in shares)	[1]	42,268
Repurchase of common stock		$ 0	[1]	0		(128)	0	0	(128)	[1]
Repurchase of common stock (in shares)	[1]	(51,366)
Balances at Dec. 31, 2016		$ 2	[1]	267,400		(5,295)	(2,329)	(202,470)	$ 57,308	[1]
Balances (in shares) at Dec. 31, 2016		18,548,180	[1]						18,548,180
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		$ 0	[1]	0		0	0	(1,526)	$ (1,526)	[1]
Partial shares in reverse split		$ 0	[1]	(1)		0	0	0	(1)	[1]
Partial shares in reverse split (in shares)	[1]	(40)
Other comprehensive income (loss)		$ 0	[1]	0		0	221	0	221	[1]
Stock-based compensation expense		0	[1]	430		0	0	0	430	[1]
Issuance of common stock upon exercise of stock options for cash and releases of RSUs		$ 0	[1]	0		0	0	0	0	[1]
Issuance of common stock upon exercise of stock options for cash and releases of RSUs (in shares)	[1]	153,824
Issuance of common stock under employee stock purchase plan		$ 0	[1]	28		0	0	0	28	[1]
Issuance of common stock under employee stock purchase plan (in shares)	[1]	28,018
Repurchase of common stock		$ 0	[1]	0		(2)	0	0	(2)	[1]
Repurchase of common stock (in shares)	[1]	(1,070)
Balances at Dec. 31, 2017		$ 2	[1]	$ 267,857		$ (5,297)	$ (2,108)	$ (203,996)	$ 56,458	[1]
Balances (in shares) at Dec. 31, 2017		18,728,912	[1]						18,728,912

[1] Prior periods adjusted to reflect the impact of the one-for-three reverse stock split that became effective on January 20, 2017, as discussed in Note 1.