Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net income (loss)	$ (28,369)	$ 61,192	$ 49,106
Adjustments to reconcile net income (loss) to cash provided by operating activities, net of the effects of acquisitions:
Depreciation and amortization	140,071	19,709	18,260
Loss on disposal of fixed assets	134	300	39
Deal related compensation expense and accretion charges	6,728	153	151
Share-based compensation expense associated with equity awards	28,351	16,580	12,930
Net change in fair value of contingent and contractual liabilities	0	(10)	(303)
Deferred income taxes	(42,121)	2,736	5,214
Other (gains) losses	(279)	168	(86)
Changes in assets and liabilities
Accounts receivable and unbilled costs	(23,259)	(21,801)	13,451
Due from related party	(18,483)	0	0
Inventories	5,523	(499)	(6,798)
Prepaid expenses and other assets	(29,481)	(2,169)	(2,841)
Accounts payable	2,334	1,355	1,498
Accrued compensation and other expenses	33,250	13,233	6,734
Due to related party	(6,743)	0	0
Income taxes payable	1,984	(684)	677
Deferred revenue	25,645	16,670	12,914
Net cash provided by operating activities	95,285	106,933	110,946
Cash flows from investing activities:
Purchase of marketable securities	(100,278)	(133,212)	(128,122)
Proceeds from maturity of marketable securities	118,881	89,954	65,570
Purchase of fixed assets	(24,783)	(12,808)	(13,066)
Purchase of intangible assets	(3,962)	(174)	(1,086)
Acquisition of businesses, net of cash acquired	27,700	0	0
Decrease (increase) in deposits	(150)	55	123
Collection of contingently returnable consideration	9,306	0	0
Capitalized software development costs	(1,625)	0	0
Net cash provided by (used in) investing activities	25,089	(56,185)	(76,581)
Cash flows from financing activities:
Issuance of common stock under stock plans	1	140	812
Payment of contingent consideration	0	0	(841)
Treasury stock repurchases	(311,850)	(51,714)	(34,322)
Proceeds from issuance of long-term debt, net of issuance costs	294,623	0	0
Excess tax benefit from share-based compensation awards	1,926	2,814	2,388
Net cash used in financing activities	(15,300)	(48,760)	(31,963)
Effect of exchange rate changes on cash and cash equivalents	744	829	(256)
Net increase in cash and cash equivalents	105,818	2,817	2,146
Cash and cash equivalents, beginning of year	104,893	102,076	99,930
Cash and cash equivalents, end of year	210,711	104,893	102,076
Supplemental disclosures of cash flow information:
Cash paid for interest	3,807	0	0
Cash paid for income taxes	50,658	29,233	21,456
Non-cash transactions:
Transfers of inventory to fixed assets	1,229	940	1,781
Additions to property, plant and equipment included in accounts payable	(1,065)	(187)	124
Debt issuance costs settled through the issuance of additional debt	5,377	0	0
Issuance of common stock under employee stock purchase plans	10,560	5,889	4,995
Purchase consideration
Non-cash transactions:
Noncash business transaction	2,276,256	0	0
Contingently returnable consideration
Non-cash transactions:
Noncash business transaction	$ 29,355	$ 0	$ 0