Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Current assets:
Cash and cash equivalents	$ 192,341	$ 121,021
Short-term marketable securities	250,775	370,677
Accounts receivable, net	84,650	90,809
Inventories	90,088	80,942
Prepaid expenses and other current assets	18,009	13,748
Total current assets	635,863	677,197
Long-term marketable securities	207,795	21,718
Property and equipment, net	164,931	145,005
Goodwill	31,969	32,601
In-process research and development	14,913	15,208
Long-term deferred tax assets, net	43,336	77,502
Other assets	117,655	85,115
Total assets	1,216,462	1,054,346
Current liabilities:
Accounts payable	32,774	32,185
Accrued expenses	75,107	57,420
Deferred revenue	19,147	16,393
Other current liabilities	4,857
Total current liabilities	131,885	105,998
Other long-term liabilities	9,305	1,061
Contingent consideration	9,000	9,575
Long-term deferred tax liabilities	806	822
Total liabilities	150,996	117,456
Commitments and contingencies (Note 13)
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	451	451
Additional paid in capital	739,133	690,507
Retained earnings	602,482	399,473
Treasury stock at cost - 2,533,374 shares at March 31, 2020 and 1,903,241 shares at March 31, 2019	(265,411)	(138,852)
Accumulated other comprehensive loss	(11,189)	(14,689)
Total stockholders' equity	1,065,466	936,890
Total liabilities and stockholders' equity	$ 1,216,462	$ 1,054,346