CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
CURRENT ASSETS:
Trade receivables, allowances	$ 2,848	$ 2,355
STOCKHOLDERS' EQUITY:
Preferred stock shares authorized (in shares)	5,000	5,000
Preferred stock shares issued (in shares)	0	0
Common stock shares authorized (in shares)	100,000	100,000
Common stock shares issued (in shares)	55,208	54,893
Common stock shares outstanding (in shares)	55,208	54,893
Developed technology
OTHER ASSETS:
Intangibles, accumulated amortization	$ 137,551	$ 102,357
Other
OTHER ASSETS:
Intangibles, accumulated amortization	$ 62,378	$ 49,136