CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands	6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 178,580	$ 192,646
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	50,528	52,976
Deferred income taxes	7,086	13,294
Share-based compensation expense related to equity incentive plans	18,508	18,376
Excess tax benefit from share-based compensation	(402)	0
Convertible debt derivatives - revaluation and amortization	366	57
Amortization of convertible debenture issuance costs	110	110
Amortization of debt discount on convertible debentures	3,671	3,356
Losses on equity method investments	74	95
Gain on sale of assets	(48)	(39)
Unrealized impairment loss on available-for-sale investments	3,009	841
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable	38,793	(18,503)
Increase in inventories	(30,074)	(10,035)
Increase in deferred income on shipments to distributors	4,141	31,019
(Decrease) increase in accounts payable and accrued liabilities	(50,300)	3,328
Change in other assets and liabilities	14,017	3,926
Net cash provided by operating activities	238,059	291,447
Cash flows from investing activities:
Purchases of available-for-sale investments	(665,715)	(796,877)
Sales and maturities of available-for-sale investments	562,445	693,760
Purchase of Silicon Storage Technology, Inc, net of cash received	0	(112,707)
Investment in other assets	(5,146)	(1,433)
Proceeds from sale of assets	48	28,430
Capital expenditures	(52,449)	(65,937)
Net cash used in investing activities	(160,817)	(254,764)
Cash flows from financing activities:
Payment of cash dividend	(132,106)	(127,361)
Proceeds from sale of common stock	25,667	22,269
Excess tax benefit from share-based compensation	402	0
Net cash used in financing activities	(106,037)	(105,092)
Net decrease in cash and cash equivalents	(28,795)	(68,409)
Cash and cash equivalents at beginning of period	703,924	492,130
Cash and cash equivalents at end of period	$ 675,129	$ 423,721