CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
CURRENT ASSETS:
Trade receivables, allowances	$ 2,406	$ 2,355
OTHER ASSETS:
Intangibles, accumulated amortization	$ 52,469	$ 49,136
STOCKHOLDERS’ EQUITY:
Preferred stock shares authorized (in shares)	5,000,000	5,000,000
Preferred stock shares issued (in shares)	0	0
Common stock par value (in dollars per share)
Common stock shares authorized (in shares)	100,000,000	100,000,000
Common stock shares issued (in shares)	54,995,000	54,893,000
Common stock shares outstanding (in shares)	54,995,000	54,893,000
Developed technology
OTHER ASSETS:
Intangibles, accumulated amortization	$ 113,765	$ 102,357
Other
OTHER ASSETS:
Intangibles, accumulated amortization	$ 52,469	$ 49,136