CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED BALANCE SHEETS
Accounts receivables and contract assets, allowances	$ 401,000	$ 503,000
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	45,477	44,490
Common stock, shares outstanding	45,430	43,560
Treasury stock, shares	47	930