Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Allowance for doubtful accounts	$ 9,838	$ 6,937
Stockholders' Equity:
Preferred stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	180,000,000	180,000,000
Common stock, shares issued (in shares)	73,152,000	78,972,000
Common stock, shares outstanding (in shares)	73,152,000	78,972,000