Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 15	$ 28
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	34,845,310	34,225,778
Common stock, shares outstanding (in shares)	28,329,416	27,715,387
Treasury stock, shares (in shares)	6,515,894	6,510,391