STOCKHOLDERS' EQUITY - Schedule of Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jul. 31, 2021	Apr. 30, 2021	Jul. 31, 2020	Apr. 30, 2020	Jul. 31, 2021	Jul. 31, 2020
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Research and development, net	$ (31,792)		$ (30,148)		$ (60,940)	$ (62,560)
Selling, general and administrative	(91,376)		(77,739)		(179,022)	(154,566)
Interest expense	(2,199)		(10,123)		(7,218)	(20,812)
Income (loss) before provision of income taxes	9,517		(1,025)		10,539	(15,096)
Provision for income taxes	(4,201)		(8,345)		(4,129)	(8,692)
Net income	5,316	$ 1,094	10,587	$ (3,975)	6,410	6,612
Recurring
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Cost of revenue	(37,636)		(32,936)		(75,712)	(67,864)
Nonrecurring
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Cost of revenue	(30,505)		(29,776)		(60,385)	(61,395)
Foreign currency forward contracts | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Research and development, net	7		0		72	0
Selling, general and administrative	3		0		31	0
Income (loss) before provision of income taxes	11		0		117	0
Provision for income taxes	(2)		0		(21)	0
Net income	9		0		96	0
Foreign currency forward contracts | Recurring | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Cost of revenue	0		0		1	0
Foreign currency forward contracts | Nonrecurring | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Cost of revenue	1		0		13	0
Interest rate swap agreement | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Interest expense	0		(1,120)		(1,014)	(1,711)
Other income (expense), net	0		0		(15,655)	0
Income (loss) before provision of income taxes	0		(1,120)		(16,669)	(1,711)
Provision for income taxes	0		244		3,638	372
Net income	$ 0		$ (876)		$ (13,031)	$ (1,339)