Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 31, 2020
Current assets:
Cash and cash equivalents	$ 477,755	$ 338,489
Marketable securities	12,689	47,969
Accounts receivable and unbilled costs, net of allowance for doubtful accounts of $719 and $1,350 at December 31, 2020 and March 31, 2020, respectively	208,016	213,514
Inventories and deferred costs	26,040	22,227
Prepaid income taxes	9,566	13,505
Prepaid expenses and other current assets	28,548	24,039
Total current assets	762,614	659,743
Fixed assets, net	51,265	57,715
Operating lease right-of-use assets	63,257	68,583
Goodwill	1,714,109	1,725,680
Intangible assets, net	535,095	582,179
Deferred income taxes	6,982	6,220
Long-term marketable securities	0	2,613
Other assets	13,001	17,770
Total assets	3,146,323	3,120,503
Current liabilities:
Accounts payable	19,219	20,004
Accrued compensation	76,900	75,632
Accrued other	36,801	21,840
Income taxes payable	233	903
Deferred revenue and customer deposits	251,313	270,281
Current portion of operating lease liabilities	11,753	10,337
Total current liabilities	396,219	398,997
Other long-term liabilities	11,568	10,039
Deferred tax liability	105,510	114,394
Accrued long-term retirement benefits	38,264	34,256
Long-term deferred revenue and customer deposits	102,713	104,240
Operating lease liabilities, net of current portion	63,814	70,658
Long-term debt	450,000	450,000
Total liabilities	1,168,088	1,182,584
Commitments and contingencies (Note 14)
Preferred stock, $0.001 par value:
5,000,000 shares authorized; no shares issued or outstanding at December 31, 2020 and March 31, 2020	0	0
Common stock, $0.001 par value:
300,000,000 shares authorized; 123,867,373 and 122,006,077 shares issued and 73,438,024 and 72,220,906 shares outstanding at December 31, 2020 and March 31, 2020, respectively	124	122
Additional paid-in capital	2,936,573	2,891,553
Accumulated other comprehensive income (loss)	262	(3,160)
Treasury stock at cost, 50,429,349 and 49,785,171 shares at December 31, 2020 and March 31, 2020, respectively	(1,321,978)	(1,305,935)
Retained earnings	363,254	355,339
Total stockholders' equity	1,978,235	1,937,919
Total liabilities and stockholders' equity	$ 3,146,323	$ 3,120,503