Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 31, 2020
Current assets:
Cash and cash equivalents	$ 181,018	$ 192,341
Short-term marketable securities	305,434	250,775
Accounts receivable, net	92,990	84,650
Inventories	82,448	90,088
Prepaid expenses and other current assets	31,801	18,009
Total current assets	693,691	635,863
Long-term marketable securities	301,315	207,795
Property and equipment, net	179,364	164,931
Goodwill	79,691	31,969
Other intangibles, net	43,327	14,913
Deferred tax assets	21,233	43,336
Other assets	109,813	117,655
Total assets	1,428,434	1,216,462
Current liabilities:
Accounts payable	23,594	32,774
Accrued expenses	71,661	75,107
Deferred revenue	21,291	19,147
Other current liabilities	3,854	4,857
Total current liabilities	120,400	131,885
Contingent consideration	25,316	9,000
Deferred tax liabilities	4,303	806
Other long-term liabilities	16,974	9,305
Total liabilities	166,993	150,996
Commitments and contingencies (Note 15)
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 - 47,435,945 shares at June 30, 2019 and 47,026,226 shares at March 31, 2019 Outstanding - 45,374,278 shares at June 30, 2019 and 45,122,985 shares at March 31, 2019	452	451
Additional paid in capital	781,903	739,133
Retained earnings	771,151	602,482
Treasury stock at cost 2,658,019 shares at December 31, 2020 and 2,533,374 shares at March 31, 2020	(287,896)	(265,411)
Accumulated other comprehensive loss	(4,169)	(11,189)
Total stockholders' equity	1,261,441	1,065,466
Total liabilities and stockholders' equity	$ 1,428,434	$ 1,216,462