CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for doubtful accounts	$ 890	$ 963
Preferred stock, par value (in dollars per share)	$ 0.00015	$ 0.00015
Preferred stock, shares authorized (in shares)	5,000	5,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.00015	$ 0.00015
Common stock, shares authorized (in shares)	70,000	70,000
Common stock, shares issued (in shares)	47,414	46,400
Common stock, shares outstanding (in shares)	37,411	36,850
Treasury stock, shares (in shares)	10,003	9,550