Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common Stock and Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Treasury Stock
Beginning balance at Dec. 31, 2014		$ 76,603	$ 204,876	$ 102	$ (82,806)	$ (45,569)
Beginning balance, shares at Dec. 31, 2014			34,225,778			6,510,391
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		2,858			2,858
Unrealized gain (loss) on available-for-sale securities, net of taxes		(16)		(16)
Foreign currency translation adjustments		$ 0
Repurchase of stock, shares		0
Issuance of stock for ESPP purchase		$ 367	$ 367
Issuance of stock for ESPP purchase, shares			45,820
Exercise of stock options, net of shares withheld for employee taxes		1,561	$ 1,630			$ (69)
Exercise of stock options, net of shares withheld for employee taxes, shares			239,071			5,503
Release of restricted stock units and awards, including related stock compensation		3,059	$ 3,059
Release of restricted stock units and awards, shares			334,641
Tax benefit/(deficiency) from the stock incentive plans		(228)	$ (228)
Stock based compensation for stock options		2,411	2,411
Ending balance at Dec. 31, 2015		86,615	$ 212,115	86	(79,948)	$ (45,638)
Ending balance, shares at Dec. 31, 2015			34,845,310			6,515,894
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(39,381)			(39,381)
Unrealized gain (loss) on available-for-sale securities, net of taxes		8		8
Foreign currency translation adjustments		21		21
Repurchase of stock		(729)				$ (729)
Repurchase of stock, shares						105,750
Issuance of stock for ESPP purchase		307	$ 307
Issuance of stock for ESPP purchase, shares			45,825
Exercise of stock options, net of shares withheld for employee taxes		2,388	$ 2,565			$ (177)
Exercise of stock options, net of shares withheld for employee taxes, shares			395,515			16,359
Release of restricted stock units and awards, including related stock compensation		2,257	$ 2,257
Release of restricted stock units and awards, shares			268,912
Stock based compensation for stock options		3,854	$ 3,854
Ending balance at Dec. 31, 2016		55,340	$ 221,098	115	(119,329)	$ (46,544)
Ending balance, shares at Dec. 31, 2016			35,555,562			6,638,003
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(45,291)			(45,291)
Unrealized gain (loss) on available-for-sale securities, net of taxes		(16)		(16)
Foreign currency translation adjustments		0
Repurchase of stock		$ (328)				$ (328)
Repurchase of stock, shares		48,687				48,687
Issuance of stock for ESPP purchase		$ 328	$ 328
Issuance of stock for ESPP purchase, shares			48,750
Exercise of stock options, net of shares withheld for employee taxes		518	$ 518			$ 0
Exercise of stock options, net of shares withheld for employee taxes, shares			70,608			0
Release of restricted stock units and awards, including related stock compensation		2,661	$ 2,661
Release of restricted stock units and awards, shares			275,598
Stock based compensation for stock options		3,441	$ 3,441
Effect of change in accounting policy (1)	[1]	(6,996)			(6,996)
Ending balance at Dec. 31, 2017		$ 9,657	$ 228,046	$ 99	$ (171,616)	$ (46,872)
Ending balance, shares at Dec. 31, 2017			35,950,518			6,686,690

[1] Represents less than 10% of the Company’s outstanding accounts and other receivables.