Warranty reserves (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Movement in warranty reserves [Roll Forward]
Warranty reserves at beginning of period	$ 140	$ 90	$ 138	$ 89
Decrease in beginning balance for warranty obligations settled during the period	(5)	(5)	(49)	(20)
Foreign currency translation adjustment	0	0	2	(1)
Net increase in warranty reserves for products sold during the period	8	40	52	57
Warranty reserves at end of period	$ 143	$ 125	$ 143	$ 125