Common Stock and Stockholders' Equity - Employee Stock Purchase Plan (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Jul. 31, 2015	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Employee Stock Purchase Plan
Stock-based compensation		$ 86,300	$ 18,315
ESPP
Employee Stock Purchase Plan
Shares reserved for issuance under the plan (in shares)		926,109
Maximum offering period	27 months
Stock purchase price as a percentage of fair value (as a percent)	85.00%
Issuance of stock under employee stock purchase plan (in shares)				49,781
Remaining shares available for issuance under the plan (in shares)		599,103
Stock-based compensation		$ 2,200	$ 400
Unrecognized compensation cost		$ 1,000
Period over which unrecognized compensation cost is expected to be recognized		1 month 6 days