Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ (2,754)	$ (73,324)	$ 79,812
Adjustments to reconcile net income (loss) to cash provided by operating activities, net of the effects of acquisitions:
Depreciation and amortization	116,104	137,878	153,503
Operating lease right-of-use assets	10,504
Loss on divestiture of business	0	7,660	0
Loss on disposal of fixed assets	16	260	481
Deal related compensation expense and accretion charges	0	102	153
Share-based compensation expense associated with equity awards	50,861	56,328	47,317
Net change in fair value of contingent and contractual liabilities	798	1,614	0
Accretion of contingent consideration	(36)	(119)	0
Impairment charge	0	35,871	0
Deferred income taxes	(9,821)	(33,442)	(127,784)
Other (gains) losses	(152)	(152)	18
Changes in assets and liabilities
Accounts receivable and unbilled costs	21,472	(22,180)	84,952
Due from related party	0	172	443
Inventories	1,501	5,321	1,006
Prepaid expenses and other assets	13,839	3,034	20,147
Accounts payable	(4,288)	(3,876)	(8,929)
Accrued compensation and other expenses	32,812	19,964	(17,718)
Operating lease liabilities	(13,077)
Due to related party	0	234	(75)
Income taxes payable	(919)	(639)	(2,734)
Deferred revenue	8,163	15,132	(8,138)
Net cash provided by operating activities	225,023	149,838	222,454
Cash flows from investing activities:
Purchase of marketable securities	(117,383)	(229,769)	(114,178)
Proceeds from maturity of marketable securities	144,322	230,433	196,041
Purchase of fixed assets	(19,922)	(23,392)	(15,913)
Purchase of intangible assets	0	0	(544)
Payments related to the divestiture of business	0	(3,293)	0
Acquisition of businesses, net of cash acquired	(11,347)	0	(8,334)
Increase in deposits	(31)	(97)	(330)
Contingent purchase consideration	0	0	523
Collection of contingent consideration	52	0	0
Capitalized software development costs	0	(134)	(137)
Net cash (used in) provided by investing activities	(4,309)	(26,252)	57,128
Cash flows from financing activities:
Issuance of common stock under stock plans	2	3	1
Payment of contingent consideration	0	(2,851)	(660)
Treasury stock repurchases, including accelerated share repurchases	(175,000)	(14,468)	(501,324)
Tax withholding on restricted stock units	(11,872)	(11,969)	(13,598)
Proceeds from issuance of long-term debt, net of issuance costs	0	0	294,619
Repayment of long-term debt	(100,000)	(50,000)	0
Net cash used in financing activities	(286,870)	(79,285)	(220,962)
Effect of exchange rate changes on cash and cash equivalents	(3,427)	(5,212)	6,385
Net (decrease) increase in cash and cash equivalents	(69,583)	39,089	65,005
Cash and cash equivalents and restricted cash, beginning of year	409,820	370,731	305,726
Cash and cash equivalents and restricted cash, end of year	340,237	409,820	370,731
Supplemental disclosures of cash flow information:
Cash paid for interest	17,644	23,281	9,604
Cash paid for income taxes	13,061	13,381	18,216
Non-cash transactions:
Transfers of inventory to fixed assets	2,290	2,152	5,556
Additions to property, plant and equipment included in accounts payable	255	455	1,379
Issuance of common stock under employee stock purchase plans	14,227	15,074	17,849
Contingent consideration related to acquisition, included in accrued other	1,800	0	523
Tenant improvement allowance	0	10,171	2,104
Initial fair value of contingent consideration received as partial consideration for divestiture of business	$ 0	$ 2,257	$ 0