Organization and Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended																		1 Months Ended			0 Months Ended	1 Months Ended
	Sep. 30, 2012 Business_Segment	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2012 Largest Distributor Sales Revenue, Goods, Net Customer Concentration Risk	Sep. 30, 2011 Largest Distributor Sales Revenue, Goods, Net Customer Concentration Risk	Sep. 30, 2010 Largest Distributor Sales Revenue, Goods, Net Customer Concentration Risk	Sep. 30, 2012 Second Largest Distributor Sales Revenue, Goods, Net Customer Concentration Risk	Sep. 30, 2011 Second Largest Distributor Sales Revenue, Goods, Net Customer Concentration Risk	Sep. 30, 2010 Second Largest Distributor Sales Revenue, Goods, Net Customer Concentration Risk	Sep. 30, 2012 Selling, general and administrative	Sep. 30, 2011 Selling, general and administrative	Sep. 30, 2010 Selling, general and administrative	Sep. 30, 2012 Minimum	Sep. 30, 2012 Maximum	Sep. 30, 2012 Property and equipment Minimum	Sep. 30, 2012 Property and equipment Maximum	Sep. 30, 2012 Buildings and leasehold improvements	Sep. 30, 2012 Wafer and Die Bank	Aug. 31, 2011 Giantec Semiconductor, Inc	Aug. 31, 2011 Giantec Semiconductor, Inc	Dec. 30, 2010 Giantec Semiconductor, Inc	Dec. 30, 2010 Giantec Semiconductor, Inc	Jan. 31, 2010 Co-venturer Giantec Semiconductor, Inc
Entity Information [Line Items]
Proceeds from formation of Giantec	$ 0	$ 0	$ 3,785,000																				$ 3,800,000
Investment received from outside investors																						4,000,000
Ownership interest																					44.00%
Ownership percentage sold in Giantec																				37.00%
Ownership percentage in Giantec after sale																			19.85%
Cash and cash equivalents maturity period	90 days
Inventory aging period	1 year																	2 years
Property, equipment and leasehold improvements useful life (years)															2 years	10 years	50 years
Estimated useful lives of purchased definite lived intangible assets													6 months	8 years
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net prior service cost	0
Actuarial loss	101,000
Transition obligation	(60,000)
Advertising costs										$ 59,000	$ 57,000	$ 35,000
Option vesting term (years)	4 years
Business segment	1
Concentration Risk, largest customers (percentage)				14.00%	15.00%	15.00%	13.00%	12.00%	10.00%
Period of product warranty (months)	12 months