CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivables and contract assets, allowances	$ 661	$ 503
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000	10,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	45,193	44,490
Common stock, shares outstanding	44,899	43,560
Treasury stock, shares	294	930