Subsequent Events	6 Months Ended
Sep. 30, 2012
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Proposed Acquisition On April 30, 2012, the Company entered into an Agreement and Plan of Merger with PLX Technology, Inc (PLX). The Merger Agreement provides that, on and subject to the terms of the Merger Agreement, the Company will commence an exchange offer to purchase all of the outstanding shares of PLX common stock, $0.001 par value, in exchange for consideration, per share of PLX common stock, comprised of (i) $3.50 in cash plus (ii) 0.525 of a share of IDT common stock, without interest and less any applicable withholding taxes. The Company expects the proposed acquisition to expand the Company's core serial switching and interface business. The Company and PLX have complementary product sets, technologies and customer bases. On May 22, 2012, the Company commenced the exchange offer to purchase the outstanding shares of PLX common stock. The exchange offer was scheduled to expire at the end of the day on July 12, 2012. On July 11, 2012, the Company extended the expiration date of its exchange offer for all outstanding shares of common stock of PLX to August 9, 2012 since the applicable waiting period for regulatory review has not yet been expired or been terminated. The expiration date was further extended (most recently on October 3, 2012) and the exchange offer is now set to expire at the end of the day November 9, 2012 unless further extended. The Company has filed a registration statement with the Securities and Exchange Commission (the “SEC”) on Form S-4 relating to the shares to be issued to the stockholders of PLX in the Offer and the Merger. The Company has incurred approximately $3.1 million and $7.2 million acquisition related costs, which were included in selling general and administrative expenses on the Condensed Consolidated Statements of Operations for the three and six months ended September 30, 2012, respectively.

Subsequent Events

Proposed Acquisition

On April 30, 2012, the Company entered into an Agreement and Plan of Merger with PLX Technology, Inc (PLX). The Merger Agreement provides that, on and subject to the terms of the Merger Agreement, the Company will commence an exchange offer to purchase all of the outstanding shares of PLX common stock, $0.001 par value, in exchange for consideration, per share of PLX common stock, comprised of (i) $3.50 in cash plus (ii) 0.525 of a share of IDT common stock, without interest and less any applicable withholding taxes. The Company expects the proposed acquisition to expand the Company's core serial switching and interface business. The Company and PLX have complementary product sets, technologies and customer bases.

On May 22, 2012, the Company commenced the exchange offer to purchase the outstanding shares of PLX common stock. The exchange offer was scheduled to expire at the end of the day on July 12, 2012. On July 11, 2012, the Company extended the expiration date of its exchange offer for all outstanding shares of common stock of PLX to August 9, 2012 since the applicable waiting period for regulatory review has not yet been expired or been terminated. The expiration date was further extended (most recently on October 3, 2012) and the exchange offer is now set to expire at the end of the day November 9, 2012 unless further extended.

The Company has filed a registration statement with the Securities and Exchange Commission (the “SEC”) on Form S-4 relating to the shares to be issued to the stockholders of PLX in the Offer and the Merger.

The Company has incurred approximately $3.1 million and $7.2 million acquisition related costs, which were included in selling general and administrative expenses on the Condensed Consolidated Statements of Operations for the three and six months ended September 30, 2012, respectively.