Summary of significant accounting policies	9 Months Ended
Summary of significant accounting policies	Jul. 02, 2011
Summary of significant accounting policies [Abstract]
Summary of significant accounting policies	(2) Summary of significant accounting policies Other than the following update to the Company's revenue recognition policy, there have been no changes since the end of 2010 to the significant accounting policies followed by Sevcon. Revenue Recognition The Company recognizes revenue in certain circumstances before delivery has occurred (commonly referred to as bill and hold transactions). In such circumstances, among other things, risk of ownership has passed to the buyer, the buyer has made a written fixed commitment to purchase the finished goods, the buyer has requested the finished goods be held for future delivery as scheduled and designated by them, and no additional performance obligations exist by the Company. For these transactions, the finished goods are segregated from inventory and normal billing and credit terms are granted. Infrequently the Company enters into fixed-price non-recurring engineering contracts. Revenue from these contracts is recognized in accordance with the percentage-of-completion method of accounting.

The entire disclosure for all significant accounting policies of the reporting entity.