Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Outstanding Ordinary Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]
Beginning Balance, Amount at Jan. 31, 2020	$ 448,072	$ 15	$ 261,220	$ 768	$ 186,069
Beginning Balance, Shares at Jan. 31, 2020		33,805,609
Issuance of shares through employee equity incentive plan, Amount	6,463	$ 0	6,463	0	0
Issuance of shares through employee equity incentive plan, Shares		478,643
Issuance of shares through employee stock purchase plan, Amount	2,660	$ 0	2,660	0	0
Issuance of shares through employee stock purchase plan, Shares		83,564
Stock repurchase, Amount	(1,000)	$ 0	(1,000)	0	0
Stock repurchase, Shares		(25,719)
Stock-based compensation expense related to stock awards granted to employees and consultants	15,214	$ 0	15,214	0	0
Net unrealized losses on investments - net of tax	(363)	0	0	(363)	0
Net loss	(15,463)	0	0	0	(15,463)
Ending Balance, Amount at Apr. 30, 2020	455,583	$ 15	284,557	405	170,606
Ending Balance, Shares at Apr. 30, 2020		34,342,097
Beginning Balance, Amount at Jan. 31, 2021	$ 474,976	$ 16	347,458	1,219	126,283
Beginning Balance, Shares at Jan. 31, 2021	35,547,440	35,547,440
Issuance of shares through employee equity incentive plan, Amount	$ 6,741	$ 0	6,741	0	0
Issuance of shares through employee equity incentive plan, Shares		643,120
Issuance of shares through employee stock purchase plan, Amount	3,694	$ 0	3,694	0	0
Issuance of shares through employee stock purchase plan, Shares		82,783
Stock-based compensation expense related to stock awards granted to employees and consultants	17,128	$ 0	17,128	0	0
Net unrealized losses on investments - net of tax	(427)	0	0	(427)	0
Net loss	(10,818)	0	0	0	(10,818)
Ending Balance, Amount at Apr. 30, 2021	$ 491,294	$ 16	$ 375,021	$ 792	$ 115,465
Ending Balance, Shares at Apr. 30, 2021	36,273,343	36,273,343