Summary of Significant Accounting Policies (Revenue by Product) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 17,219	$ 17,717	$ 62,965	$ 60,376
Broadband
Disaggregation of Revenue [Line Items]
Revenue	9,761	13,650	41,238	48,195
Chips
Disaggregation of Revenue [Line Items]
Revenue	1,854	2,476	9,570	7,522
Navigation
Disaggregation of Revenue [Line Items]
Revenue	$ 5,604	$ 1,591	$ 12,157	$ 4,659
Product Concentration Risk | Revenue from Contract with Customer
Disaggregation of Revenue [Line Items]
Concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Product Concentration Risk | Revenue from Contract with Customer | Broadband
Disaggregation of Revenue [Line Items]
Concentration risk percentage	57.00%	77.00%	66.00%	80.00%
Product Concentration Risk | Revenue from Contract with Customer | Chips
Disaggregation of Revenue [Line Items]
Concentration risk percentage	11.00%	14.00%	15.00%	12.00%
Product Concentration Risk | Revenue from Contract with Customer | Navigation
Disaggregation of Revenue [Line Items]
Concentration risk percentage	32.00%	9.00%	19.00%	8.00%