CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 285	$ 428
Provision for obsolescence, inventory	$ 402	$ 439
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	33,847,100	34,061,360
Common stock, shares outstanding (in shares)	33,704,525	33,918,785