UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 1,700	$ 1,487
Term loan current, discount and prepaid costs	3,539	2,133
Term loan deferred, discount and prepaid costs	$ 11,286	$ 7,655
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares outstanding (in shares)	21,131,000	20,804,000
Treasury stock, shares (in shares)	313,000	293,000