FAIR VALUE MEASUREMENTS - Recurring Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Mar. 31, 2021
Assets measured at fair value on a recurring basis
Short-term investments	$ 1,440,631	$ 1,308,692
Contingent consideration, noncurrent	37,014
Total recurring fair value measurements, net	2,827,415	2,976,627
Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	306,204	837,614
Restricted cash and cash equivalents	751,355	528,659
Long-term restricted cash and cash equivalents	103,437	98,541
Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	115,000	95,000
Short-term investments	577,741	578,762
Restricted cash and cash equivalents	542	563
Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	19,439	100,105
Short-term investments	107,596	148,150
Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents		0
Short-term investments	707,115	521,224
US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	48,165	60,086
Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	14	470
Private equity
Assets measured at fair value on a recurring basis
Private equity	10,091	7,578
Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	(465)	(125)
Quoted prices in active markets for identical assets (level 1)
Assets measured at fair value on a recurring basis
Contingent consideration, current	0
Contingent consideration, noncurrent	0
Total recurring fair value measurements, net	1,902,444	2,199,225
Quoted prices in active markets for identical assets (level 1) | Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	306,204	837,614
Restricted cash and cash equivalents	751,355	528,659
Long-term restricted cash and cash equivalents	103,437	98,541
Quoted prices in active markets for identical assets (level 1) | Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	115,000	95,000
Short-term investments	577,741	578,762
Restricted cash and cash equivalents	542	563
Quoted prices in active markets for identical assets (level 1) | Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Quoted prices in active markets for identical assets (level 1) | Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents		0
Short-term investments	0	0
Quoted prices in active markets for identical assets (level 1) | US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	48,165	60,086
Quoted prices in active markets for identical assets (level 1) | Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Quoted prices in active markets for identical assets (level 1) | Private equity
Assets measured at fair value on a recurring basis
Private equity	0	0
Quoted prices in active markets for identical assets (level 1) | Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	0	0
Significant other observable inputs (level 2)
Assets measured at fair value on a recurring basis
Contingent consideration, current	0
Contingent consideration, noncurrent	0
Total recurring fair value measurements, net	833,699	769,824
Significant other observable inputs (level 2) | Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Long-term restricted cash and cash equivalents	0	0
Significant other observable inputs (level 2) | Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Restricted cash and cash equivalents	0	0
Significant other observable inputs (level 2) | Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	19,439	100,105
Short-term investments	107,596	148,150
Significant other observable inputs (level 2) | Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents		0
Short-term investments	707,115	521,224
Significant other observable inputs (level 2) | US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Significant other observable inputs (level 2) | Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	14	470
Significant other observable inputs (level 2) | Private equity
Assets measured at fair value on a recurring basis
Private equity	0	0
Significant other observable inputs (level 2) | Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	(465)	(125)
Significant unobservable inputs (level 3)
Assets measured at fair value on a recurring basis
Contingent consideration, current	44,167
Contingent consideration, noncurrent	37,014
Total recurring fair value measurements, net	91,272	7,578
Significant unobservable inputs (level 3) | Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Long-term restricted cash and cash equivalents	0	0
Significant unobservable inputs (level 3) | Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Restricted cash and cash equivalents	0	0
Significant unobservable inputs (level 3) | Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Significant unobservable inputs (level 3) | Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents		0
Short-term investments	0	0
Significant unobservable inputs (level 3) | US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Significant unobservable inputs (level 3) | Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Significant unobservable inputs (level 3) | Private equity
Assets measured at fair value on a recurring basis
Private equity	10,091	7,578
Significant unobservable inputs (level 3) | Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	$ 0	$ 0