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, 2013		$ 2	[1]	$ 258,294		$ (5,036)	$ (1,874)	$ (155,990)	$ 95,396	[1]
Balances (in shares) at Dec. 31, 2013	[1]	17,760,665
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		$ 0	[1]	0		0	0	(3,483)	(3,483)	[1]
Other comprehensive loss				0		0	(154)	0	(154)	[1]
Stock-based compensation expense		0	[1]	2,874		0	0	0	2,874	[1]
Issuance of common stock upon exercise of stock options for cash and releases of RSUs		$ 0	[1]	874		0	0	0	874	[1]
Issuance of common stock upon exercise of stock options for cash and releases of RSUs (in shares)	[1]	288,318
Issuance of common stock under employee stock purchase plan		$ 0	[1]	222		0	0	0	222	[1]
Issuance of common stock under employee stock purchase plan (in shares)	[1]	39,178
Utilized excess tax benefit		$ 0	[1]	(8)		0	0	0	(8)	[1]
Balances at Dec. 31, 2014		$ 2	[1]	262,256		(5,036)	(2,028)	(159,473)	95,721	[1]
Balances (in shares) at Dec. 31, 2014	[1]	18,088,161
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		$ 0	[1]	0		0	0	(27,041)	(27,041)	[1]
Other comprehensive loss		0	[1]	0		0	(274)	0	(274)	[1]
Stock-based compensation expense		0	[1]	2,914		0	0	0	2,914	[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]	184,495
Issuance of common stock under employee stock purchase plan		$ 0	[1]	157		0	0	0	157	[1]
Issuance of common stock under employee stock purchase plan (in shares)	[1]	47,250
Repurchase of common stock		$ 0	[1]	0		(131)	0	0	(131)	[1]
Repurchase of common stock (in shares)	[1]	(32,945)
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		18,286,961	[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 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

[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.