Stock-based Compensation - Summary of Nonvested Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Shares
Number of shares outstanding (in shares)	1,148,301	1,709,589	2,735,572
Granted (in shares)	1,449,779	0	108,288
Vested (in shares)	(496,464)	(547,537)	(1,032,910)
Forfeited (in shares)	(68,580)	(13,751)	(101,361)
Number of shares outstanding (in shares)	2,033,036	1,148,301	1,709,589
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, outstanding (in usd per share)	$ 0.95	$ 0.82	$ 0.73
Granted (in usd per share)	4.49	0	1.73
Vested (in usd per share)	0.08	0.85	0.62
Forfeited (in usd per share)	1.32	0.77	1.07
Weighted average grant date fair value, outstanding (in usd per share)	$ 3.49	$ 0.95	$ 0.82