Subsequent Events	12 Months Ended
Mar. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Completion of Acquisition of Supertex Inc. On April 1, 2014, the Company closed its acquisition of Supertex Inc. Upon the closing of the acquisition, each share of common stock of Supertex was canceled and automatically converted into the right to receive $33.00 in cash without interest and less any applicable withholding taxes. The amount of cash paid by the Company, net of cash and short-term investments from Supertex of approximately $155.8 million, was approximately $234.2 million. The Company financed the transaction using borrowings under its existing credit agreement. Supertex is a leader in high voltage analog and mixed-signal products for the medical, lighting and industrial control markets. Supertex is headquartered in Sunnyvale, California and has offices, manufacturing and research facilities in California and Hong Kong. Announcement of Signing of Definitive Agreement to Acquire ISSC On May 22, 2014, the Company announced a definitive agreement to acquire ISSC Technologies Corporation (ISSC), a leading provider of low power Bluetooth and advanced wireless solutions for the Internet Of Things (IoT) market. ISSC is publicly traded on the GreTai Securities Market and is headquartered in Hsinchu, Taiwan with sales or research subsidiaries in Shenzhen, China and Torrance, California. Under the terms of the transaction, the Company will commence a tender offer through its indirect wholly owned Cayman Island subsidiary (the "Cayman Subsidiary") to acquire all of the outstanding shares of ISSC for approximately $4.74 per share ($143 New Taiwan (NT) dollars per share, based on an assumed exchange rate of NT$30.15 per U.S. dollar) in cash, and acquire any remaining shares pursuant to a follow-on merger at approximately $4.74 per share minus any dividends paid by ISSC prior to the close of the transaction. The transaction represents a total equity value of about $328.5 million (approximately NT$9.9 billion), and a total enterprise value of about $294.3 million (approximately NT$8.9 billion), after excluding ISSC’s cash and investments on its balance sheet of approximately $34.2 million (approximately NT$1.0 billion). Upon completion of the tender offer through the Cayman Subsidiary, the Company will own the majority of the outstanding shares of ISSC and will consolidate ISSC’s financial statements.

SUBSEQUENT EVENTS

Completion of Acquisition of Supertex Inc.

On April 1, 2014, the Company closed its acquisition of Supertex Inc. Upon the closing of the acquisition, each share of common stock of Supertex was canceled and automatically converted into the right to receive $33.00 in cash without interest and less any applicable withholding taxes. The amount of cash paid by the Company, net of cash and short-term investments from Supertex of approximately $155.8 million, was approximately $234.2 million. The Company financed the transaction using borrowings under its existing credit agreement. Supertex is a leader in high voltage analog and mixed-signal products for the medical, lighting and industrial control markets. Supertex is headquartered in Sunnyvale, California and has offices, manufacturing and research facilities in California and Hong Kong.

Announcement of Signing of Definitive Agreement to Acquire ISSC

On May 22, 2014, the Company announced a definitive agreement to acquire ISSC Technologies Corporation (ISSC), a leading provider of low power Bluetooth and advanced wireless solutions for the Internet Of Things (IoT) market. ISSC is publicly traded on the GreTai Securities Market and is headquartered in Hsinchu, Taiwan with sales or research subsidiaries in Shenzhen, China and Torrance, California. Under the terms of the transaction, the Company will commence a tender offer through its indirect wholly owned Cayman Island subsidiary (the "Cayman Subsidiary") to acquire all of the outstanding shares of ISSC for approximately $4.74 per share ($143 New Taiwan (NT) dollars per share, based on an assumed exchange rate of NT$30.15 per U.S. dollar) in cash, and acquire any remaining shares pursuant to a follow-on merger at approximately $4.74 per share minus any dividends paid by ISSC prior to the close of the transaction. The transaction represents a total equity value of about $328.5 million (approximately NT$9.9 billion), and a total enterprise value of about $294.3 million (approximately NT$8.9 billion), after excluding ISSC’s cash and investments on its balance sheet of approximately $34.2 million (approximately NT$1.0 billion). Upon completion of the tender offer through the Cayman Subsidiary, the Company will own the majority of the outstanding shares of ISSC and will consolidate ISSC’s financial statements.