CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012
Current Assets:
Cash and cash equivalents	$ 13,415	$ 19,860
Short-term investments	134,258	111,137
Trade accounts receivable, net	7,754	8,021
Inventories	12,924	14,438
Prepaid expenses and other current assets	6,914	6,786
Prepaid income taxes	3,017	3,032
Deferred income taxes	7,545	7,529
Total current assets	185,827	170,803
Long-term investments	13,600	25,900
Property, plant and equipment, net	4,674	4,941
Other assets	585	621
Deferred income taxes, noncurrent	5,344	5,375
Total assets	210,030	207,640
Current Liabilities:
Trade accounts payable	2,472	1,994
Accrued salaries and employee benefits	12,170	12,434
Other accrued liabilities	610	615
Deferred revenue	2,600	2,560
Income taxes payable	234	23
Total current liabilities	18,086	17,626
Income taxes payable, noncurrent	4,148	4,161
Deferred tax liabilities, noncurrent	127
Other accrued liabilities, noncurrent	564	561
Total liabilities	22,925	22,348
Commitments and contingencies (Note 9)
Preferred stock, no par value -- 10,000 shares authorized; none issued and outstanding
Common stock, no par value -- 30,000 shares authorized; issued and outstanding 12,004 shares as of June 30, 2012 and 11,992 shares as of March 31, 2012	69,060	68,031
Accumulated other comprehensive loss	(1,081)	(1,345)
Retained earnings	119,126	118,606
Total shareholders' equity	187,105	185,292
Total liabilities and shareholders' equity	$ 210,030	$ 207,640