CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013
Current assets:
Cash and cash equivalents	$ 245,980	$ 228,776
Short-term investments	113,143	116,581
Accounts receivable, net	123,748	128,209
Inventory, net	69,150	67,435
Deferred tax assets	10,065	10,120
Other current assets	15,289	15,369
Total current assets	577,375	566,490
Long-term investments	79,475	80,261
Property, plant, and equipment, net	118,318	99,111
Goodwill and purchased intangibles, net	16,265	16,440
Other assets	2,240	2,303
Total assets	793,673	764,605
Current liabilities:
Accounts payable	29,500	37,067
Accrued liabilities	60,926	66,419
Total current liabilities	90,426	103,486
Deferred tax liabilities	2,833	1,742
Long-term income taxes payable	12,685	12,005
Other long-term liabilities	1,686	925
Total liabilities	107,630	118,158
Commitments and contingencies (Note 7)
Stockholders' equity:
Common stock	769	757
Additional paid-in capital	645,169	612,283
Accumulated other comprehensive income	1,858	5,567
Retained earnings	69,670	28,344
Total stockholders' equity before treasury stock	717,466	646,951
Less: Treasury stock, at cost	(31,423)	(504)
Total stockholders' equity	686,043	646,447
Total liabilities and stockholders' equity	$ 793,673	$ 764,605