Stock-Based Compensation - Stock Options (Details) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares
Employee and non-employee stock options
Stock Based Compensation
Shares available for grant, beginning balance	3,197,000
Additional shares authorized	3,446,000
Options granted (in shares)	(150,000)
Options forfeited (in shares)	17,000
RSUs granted (in shares)	(1,180,000)
RSUs forfeited/cancelled (in shares)	78,000
Shares available for grant, end balance	5,408,000	3,197,000
Number of shares
Outstanding, beginning balance (in shares)	6,707,000
Options granted (in shares)	150,000
Options exercised (in shares)	(575,000)
Options forfeited (in shares)	(17,000)
Outstanding, end balance (in shares)	6,265,000	6,707,000
Exercisable (in shares)	4,796,000
Vested and expected to vest (in shares)	6,176,000
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 11.19
Granted (in dollars per share) | $ / shares	119.73
Exercised (in dollars per share) | $ / shares	7.95
Forfeited (in dollars per share) | $ / shares	12.64
Outstanding, end balance (in dollars per share) | $ / shares	14.09	$ 11.19
Exercisable (in dollars per share) | $ / shares	9.51
Vested and expected to vest (in dollars per share) | $ / shares	$ 13.87
Additional disclosures
Weighted average contractual term, options outstanding	5 years 11 months 23 days	6 years 14 days
Exercisable (in years)	5 years 4 months 2 days
Vested and expected to vest (in years)	5 years 11 months 12 days
Aggregate intrinsic value, options outstanding | $	$ 550,649	$ 592,468
Aggregate intrinsic value, options exercisable | $	441,349
Aggregate intrinsic value, vested and expected to vest | $	$ 544,020
Non-employee stock options
Stock Based Compensation
Options granted (in shares)	(34,376)
Number of shares
Options granted (in shares)	34,376
Additional disclosures
Options unvested (in shares)	2,917
Restricted stock units
Stock Based Compensation
RSUs granted (in shares)	(1,180,000)
RSUs forfeited/cancelled (in shares)	78,000