CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 162
Accounts receivable, allowance for sales returns and doubtful accounts		$ 597
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	20,000,000	20,000,000
Common stock, issued	12,141,000	12,103,000
Common stock, outstanding	11,951,000	11,971,000
Treasury stock, common, shares	128,000