CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (loss) [Member]	Total
Balance at Dec. 31, 2010	$ 14	$ 90,423	$ 6,736	$ (1,756)	$ 95,417
Balance (in shares) at Dec. 31, 2010	13,629,713				13,629,713
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee purchase plan	0	276	0	0	276
Issuance of common stock for employee purchase plan (in shares)	45,161
Exercise of stock options	0	1,230	0	0	1,230
Exercise of stock options (in shares)	207,624
Issuance of common stock in settlement of restricted stock units, net of shares withheld for employee taxes, and stock awards	0	(146)	0	0	(146)
Issuance of common stock in settlement of restricted stock units, net of shares withheld for employee taxes, and stock awards (in shares)	65,897
Stock-based compensation expense	0	3,907	0	0	3,907
Tax benefit from exercises of stock-based payment awards	0	29	0	0	29
Components of other comprehensive loss:
Net loss	0	0	(10,061)	0	(10,061)
Net change in unrealized gain (loss) on available-for-sale investments	0	0	0	915	915
Balance at Dec. 31, 2011	14	95,719	(3,325)	(841)	91,567
Balance (in shares) at Dec. 31, 2011	13,948,395				13,948,395
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee purchase plan	0	289	0	0	289
Issuance of common stock for employee purchase plan (in shares)	46,982
Exercise of stock options	0	1,480	0	0	1,480
Exercise of stock options (in shares)	211,551
Issuance of common stock in settlement of restricted stock units, net of shares withheld for employee taxes, and stock awards	0	(101)	0	0	(101)
Issuance of common stock in settlement of restricted stock units, net of shares withheld for employee taxes, and stock awards (in shares)	26,548
Stock-based compensation expense	0	3,159	0	0	3,159
Tax benefit from exercises of stock-based payment awards	0	6	0	0	6
Components of other comprehensive loss:
Net loss	0	0	(6,548)	0	(6,548)
Net change in unrealized gain (loss) on available-for-sale investments	0	0	0	922	922
Balance at Dec. 31, 2012	14	100,552	(9,873)	81	90,774
Balance (in shares) at Dec. 31, 2012	14,233,476				14,233,476
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee purchase plan	0	362	0	0	362
Issuance of common stock for employee purchase plan (in shares)	51,338
Exercise of stock options	1	5,048	0	0	5,049
Exercise of stock options (in shares)	612,210
Issuance of common stock in settlement of restricted stock units, net of shares withheld for employee taxes, and stock awards	0	(222)	0	0	(222)
Issuance of common stock in settlement of restricted stock units, net of shares withheld for employee taxes, and stock awards (in shares)	95,256
Repurchase of common stock	(1)	(10,030)	0		(10,031)
Repurchase of common stock (in shares)	(1,060,447)
Stock-based compensation expense	0	3,110	0	0	3,110
Components of other comprehensive loss:
Net loss	0	0	(4,747)	0	(4,747)
Net change in unrealized gain (loss) on available-for-sale investments	0	0	0	(30)	(30)
Balance at Dec. 31, 2013	$ 14	$ 98,820	$ (14,620)	$ 51	$ 84,265
Balance (in shares) at Dec. 31, 2013	13,931,833				13,931,833