CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013
Current assets:
Cash and cash equivalents	$ 82,062	$ 40,418
Restricted cash and investments	14,455	12,618
Short-term investments, at fair value	60,412	108,546
Accounts receivable, net of allowances of $420 and $351 at June 30, 2013 and March 31, 2013, respectively	25,269	28,477
Unbilled costs and fees	5,230	4,875
Inventories, net	50,375	48,051
Prepaid expenses and other current assets	6,671	8,829
Deferred income taxes	3,155	3,155
Total current assets	247,629	254,969
Building, equipment and leasehold improvements, net	15,867	16,451
Restricted cash and investments	859	899
Deferred income taxes	8,325	8,325
Other assets, net	1,004	805
Total assets	273,684	281,449
Current liabilities:
Accounts payable	9,004	8,371
Accrued salaries and benefits	9,158	9,974
Accrued warranty costs	364	397
Accrued income taxes	2,938	2,094
Deferred revenue	15,107	15,770
Customer deposits	20,965	16,199
Current portion of lease financing liability	1,495	1,489
Other current liabilities	12,440	14,194
Total current liabilities	71,471	68,488
Lease financing liability, net of current portion	2,539	2,914
Deferred revenue	4,825	5,535
Other long-term liabilities	204	267
Total liabilities	79,039	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 7,814,490 and 7,980,202 shares issued and outstanding at June 30, 2013 and March 31, 2013, respectively	5,208	5,320
Capital in excess of par value	31,013	41,458
Accumulated other comprehensive loss, net	(30)	(4)
Retained earnings	158,454	157,471
Total stockholders' equity	194,645	204,245
Total liabilities and stockholders' equity	$ 273,684	$ 281,449