CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
CONSOLIDATED BALANCE SHEETS
Valuation allowance	$ 53,609	$ 50,652
Common stock, shares authorized (in shares)	90,000,000	90,000,000
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares issued (in shares)	25,701,115	25,623,016
Common stock, shares outstanding (in shares)	25,234,572	25,444,275
Treasury stock, at cost	466,543	178,741