Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013
Current assets:
Cash and cash equivalents	$ 10,120	$ 9,451
Short-term marketable securities	60,950	67,256
Accounts receivable, net	21,119	22,946
Inventories	15,636	14,930
Prepaid expenses and other current assets	2,789	2,022
Total current assets	110,614	116,605
Long-term marketable securities	25,811	11,406
Property and equipment, net	6,444	6,549
Goodwill	37,349	35,410
Other assets	801	29
Total assets	181,019	169,999
Current liabilities:
Accounts payable	6,182	7,696
Accrued expenses	13,722	15,162
Deferred revenue	4,142	4,198
Total current liabilities	24,046	27,056
Long-term deferred tax liability	6,007	5,554
Other long-term liabilities	262	309
Total liabilities	30,315	32,919
Commitments and contingencies
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 - 40,659,164 shares at September 30, 2013 and 39,788,383 shares at March 31, 2013; Outstanding - 39,452,797 shares at September 30, 2013 and 38,601,384 shares at March 31, 2013	406	397
Additional paid in capital	427,183	414,810
Accumulated deficit	(258,925)	(258,261)
Treasury stock at cost - 1,206,367 shares at September 30, 2013 and 1,186,999 shares at March 31, 2013	(16,554)	(16,129)
Accumulated other comprehensive loss	(1,406)	(3,737)
Total stockholders' equity	150,704	137,080
Total liabilities and stockholders' equity	$ 181,019	$ 169,999