Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Current assets:
Cash and cash equivalents	$ 467,176	$ 338,489
Marketable securities	9,277	47,969
Accounts receivable and unbilled costs, net of allowance for doubtful accounts of $416 and $1,350 at March 31, 2021 and 2020, respectively	197,717	213,514
Inventories and deferred costs	22,813	22,227
Prepaid income taxes	1,906	13,505
Prepaid expenses and other current assets	23,583	24,039
Total current assets	722,472	659,743
Fixed assets, net	48,474	57,715
Operating lease right-of-use assets	61,512	68,583
Goodwill	1,717,554	1,725,680
Intangible assets, net	511,866	582,179
Deferred income taxes	8,096	6,220
Long-term marketable securities	0	2,613
Other assets	15,064	17,770
Total assets	3,085,038	3,120,503
Current liabilities:
Accounts payable	17,964	20,004
Accrued compensation	83,057	75,632
Accrued other	21,127	21,840
Income taxes payable	7,025	903
Deferred revenue and customer deposits	269,748	270,281
Current portion of operating lease liabilities	12,354	10,337
Total current liabilities	411,275	398,997
Other long-term liabilities	21,641	10,039
Deferred tax liability	92,287	114,394
Accrued long-term retirement benefits	39,479	34,256
Long-term deferred revenue and customer deposits	103,310	104,240
Operating lease liabilities, net of current portion	61,267	70,658
Long-term debt	350,000	450,000
Total liabilities	1,079,259	1,182,584
Commitments and contingencies (Note 19)
Stockholders’ equity:
Preferred stock, $0.001 par value: 5,000,000 shares authorized; no shares issued or outstanding at March 31, 2021 and 2020	0	0
Common stock, $0.001 par value: 300,000,000 shares authorized; 124,197,974 and 122,006,077 shares issued and 73,751,615 and 72,220,906 shares outstanding at March 31, 2021 and 2020, respectively	124	122
Additional paid-in capital	2,955,400	2,891,553
Accumulated other comprehensive loss	(1,940)	(3,160)
Treasury stock at cost, 50,446,359 and 49,785,171 shares at March 31, 2021 and 2020, respectively	(1,322,496)	(1,305,935)
Retained earnings	374,691	355,339
Total stockholders’ equity	2,005,779	1,937,919
Total liabilities and stockholders’ equity	$ 3,085,038	$ 3,120,503