CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Allowance for doubtful accounts	$ 2,061	$ 2,232
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	53,092,328	51,839,527
Common stock, shares outstanding (in shares)	52,430,947	51,178,146
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	1	1
Preferred stock, shares outstanding (in shares)	1	1
Par value of common stock (in dollars per share)	$ 0.0001	$ 0.0001
Treasury stock (in shares)	661,381	661,381
Series B Convertible Stock
Series B convertible preferred stock par value (in dollars per share)	$ 0.0001
Series B convertible preferred stock, shares authorized (in shares)	150,000
Series B convertible preferred stock, shares issued (in shares)	150,000	0
Series B convertible preferred stock, shares outstanding (in shares)	150,000
Treasury Stock
Par value of common stock (in dollars per share)	$ 0.0001	$ 0.0001