CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013
Current assets:
Cash and cash equivalents	$ 256,343	$ 228,776
Short-term investments	101,610	116,581
Accounts receivable, net	120,903	128,209
Inventory, net	65,314	67,435
Deferred tax assets	10,193	10,120
Other current assets	13,909	15,369
Total current assets	568,272	566,490
Long-term investments	85,904	80,261
Property, plant, and equipment, net	107,814	99,111
Goodwill and purchased intangibles, net	16,349	16,440
Other assets	2,181	2,303
Total assets	780,520	764,605
Current liabilities:
Accounts payable	32,727	37,067
Accrued liabilities	57,394	66,419
Total current liabilities	90,121	103,486
Deferred tax liabilities	3,861	1,742
Long-term income taxes payable	12,145	12,005
Other long-term liabilities	824	925
Total liabilities	106,951	118,158
Commitments and contingencies (Note 7)
Stockholders' equity:
Common stock	767	757
Additional paid-in capital	633,988	612,283
Accumulated other comprehensive income	3,181	5,567
Retained earnings	50,929	28,344
Total stockholders' equity before treasury stock	688,865	646,951
Less: Treasury stock, at cost	(15,296)	(504)
Total stockholders' equity	673,569	646,447
Total liabilities and stockholders' equity	$ 780,520	$ 764,605