CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013
Current assets:
Cash and cash equivalents	$ 86,469	$ 40,418
Restricted cash and investments	13,878	12,618
Short-term investments, at fair value	68,501	108,546
Accounts receivable, net of allowances of $319 and $351 at September 30, 2013 and March 31, 2013, respectively	21,019	28,477
Unbilled costs and fees	4,870	4,875
Inventories, net	50,808	48,051
Prepaid expenses and other current assets	7,165	8,829
Deferred income taxes	1,582	3,155
Total current assets	254,292	254,969
Building, equipment and leasehold improvements, net	15,087	16,451
Restricted cash and investments	861	899
Deferred income taxes	8,004	8,325
Other assets, net	829	805
Total assets	279,073	281,449
Current liabilities:
Accounts payable	11,244	8,371
Accrued salaries and benefits	8,522	9,974
Accrued warranty costs	345	397
Accrued income taxes		2,094
Deferred revenue	13,974	15,770
Customer deposits	28,930	16,199
Current portion of lease financing liability	1,500	1,489
Other current liabilities	11,994	14,194
Total current liabilities	76,509	68,488
Lease financing liability, net of current portion	2,161	2,914
Deferred revenue	4,254	5,535
Other long-term liabilities	215	267
Total liabilities	83,139	77,204
Stockholders' equity:
Preferred stock, no par value, 100,000 shares authorized; no shares issued
Common stock, $0.66 2/3 par value, 20,000,000 shares authorized 7,833,192 and 7,980,202 shares issued and outstanding at September 30, 2013 and March 31, 2013, respectively	5,222	5,320
Capital in excess of par value	31,397	41,458
Accumulated other comprehensive income (loss), net	29	(4)
Retained earnings	159,286	157,471
Total stockholders' equity	195,934	204,245
Total liabilities and stockholders' equity	$ 279,073	$ 281,449