CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012
Current assets:
Cash and cash equivalents	$ 84,316	$ 69,780
Restricted cash	22,269	22,269
Short-term investments	100,601	106,674
Trade receivables, net of allowances of $605 and $390	28,110	32,744
Inventories	70,492	68,055
Shipped systems pending acceptance	357	1,360
Deferred income taxes, net	9,950	10,021
Other current assets	4,480	4,060
Total current assets	320,575	314,963
Non-current investments	12,994	23,046
Property, plant and equipment, net of accumulated depreciation of $102,806 and $101,716	31,030	32,103
Non-current deferred income taxes, net	38,141	36,489
Goodwill	8,150	4,014
Acquired intangible assets, net of accumulated amortization of $11,080 and $10,609	13,526	8,332
Other assets	14,993	14,263
Total assets	439,409	433,210
Current liabilities:
Accounts payable	18,466	13,045
Accrued liabilities	22,838	21,635
Deferred revenue	10,676	10,751
Total current liabilities	51,980	45,431
Non-current income taxes payable	9,414	9,109
Commitments and contingencies
Shareholders' equity:
Preferred stock, without par value; 1,000 shares authorized; no shares issued
Common stock, without par value; 100,000 shares authorized; 29,263 and 28,970 issued and outstanding	170,557	168,143
Retained earnings	206,746	210,021
Accumulated other comprehensive income	712	506
Total shareholders' equity	378,015	378,670
Total liabilities and shareholders' equity	$ 439,409	$ 433,210