Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Income Tax Disclosure [Abstract]
Tax at federal statutory rate	$ 5,536	$ 1,764	$ (1,157)
State taxes	14	67	45
Foreign rate differential	(2,096)	(1,627)	(26)
Stock-based compensation	(32,070)	1,662	3,272
Permanent items	1,009	809	117
Research and development credits	(2,808)	(289)	(150)
Tax uncertainties	1,019	515	516
Change in valuation allowance	30,932	(1,438)	(1,537)
Change in federal tax rate	0	0	(881)
Other	(479)	(698)	105
Total provision for income taxes	$ 1,057	$ 765	$ 304
Effective tax rate	4.00%	9.20%	(8.60%)