Stockholders Equity - RSU and RSA activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Weighted-average grant date fair value (per share)
Stock-based compensation	$ 1,600	$ 1,400
Non-cash compensation expense not yet charged to net income	$ 14,300	$ 13,700
RSAs | Certain employees
Number of shares
Outstanding, Beginning balance	872,079
Granted (in shares)	185,586
Vested (in shares)	(115,604)
Canceled (in shares)	(1,547)
Outstanding, Ending balance	940,514	872,079
Grant date fair value
Beginning balance	$ 13,737
Granted	2,379
Vested	(1,801)
Canceled	(21)
Ending balance	$ 14,294	$ 13,737
Weighted-average grant date fair value (per share)
Beginning balance	$ 15.75
Granted (in per share)	12.82
Vested (in per share)	15.58
Canceled (in per share)	13.50
Ending balance	$ 15.20	$ 15.75