Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Current assets:
Cash and cash equivalents	$ 232,710	$ 192,341
Short-term marketable securities	350,985	250,775
Accounts receivable, net	97,179	84,650
Inventories	81,059	90,088
Prepaid expenses and other current assets	26,032	18,009
Total current assets	787,965	635,863
Long-term marketable securities	264,085	207,795
Property and equipment, net	197,129	164,931
Goodwill	78,568	31,969
Other intangibles, net	42,150	14,913
Deferred tax assets	11,380	43,336
Other assets	113,082	117,655
Total assets	1,494,359	1,216,462
Current liabilities:
Accounts payable	34,842	32,774
Accrued expenses	66,046	75,107
Deferred revenue	24,322	19,147
Other current liabilities	3,759	4,857
Total current liabilities	128,969	131,885
Other long-term liabilities	10,162	9,305
Contingent consideration	24,706	9,000
Deferred tax liabilities	847	806
Total liabilities	164,684	150,996
Commitments and contingencies (Note 16)
Stockholders' equity:
Class B Preferred stock, $.01 par value Authorized - 1,000,000 shares; Issued and outstanding - none
Common stock, $.01 par value Authorized - 100,000,000 shares; Issued - 47,542,061 shares at March 31, 2020 and 47,026,226 shares at March 31, 2019; Outstanding - 45,008,687 shares at March 31, 2020 and 45,122,985 shares at March 31, 2019	453	451
Additional paid in capital	800,690	739,133
Retained earnings	828,007	602,482
Treasury stock at cost 2,658,454 shares as of March 31, 2021 and 2,533,374 shares as of March 31, 2020	(288,030)	(265,411)
Accumulated other comprehensive loss	(11,445)	(11,189)
Total stockholders' equity	1,329,675	1,065,466
Total liabilities and stockholders' equity	$ 1,494,359	$ 1,216,462