CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 1,418	$ 1,487
Term loan current, discount and prepaid costs	3,912	2,133
Term loan deferred, discount and prepaid costs	$ 10,625	$ 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 issued (in shares)	21,302,000	20,804,000
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares outstanding (in shares)	21,302,000	20,804,000
Treasury stock, shares (in shares)	329,000	293,000