CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Trade receivables, allowances	$ 5,652	$ 5,313
Stockholders' equity:
Preferred stock shares authorized (in shares)	5,000	5,000
Preferred stock shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock shares authorized (in shares)	100,000	100,000
Common stock shares issued (in shares)	56,224	55,623
Common stock shares outstanding (in shares)	56,224	55,623
Developed technology
Other assets:
Intangibles, accumulated amortization	$ 213,621	$ 193,164
Other
Other assets:
Intangibles, accumulated amortization	$ 60,993	$ 56,943