Income Taxes - Net deferred tax assets (liabilities) (Details) - USD ($)	Sep. 30, 2019	Sep. 30, 2018
Domestic [Member]
Income Tax [Line Items]
Credits	$ 3,501,000	$ 3,530,000
NOLs	2,974,000	3,235,000
Stock compensation	202,000	203,000
Accruals	310,000	209,000
Other	126,000	109,000
Gross deferred tax assets	7,113,000	7,286,000
Valuation allowance	(1,916,000)	(1,777,000)
Net deferred tax assets	5,197,000	5,509,000
Depreciation	(1,194,000)	(1,168,000)
Intangibles	41,000	(7,000)
Other	0
Gross deferred tax liabilities	(1,153,000)	(1,175,000)
Net deferred tax asset (liability)	4,044,000	4,334,000
Foreign [Member]
Income Tax [Line Items]
Credits	0
NOLs	24,000	25,000
Stock compensation	0
Accruals	0
Other	0
Gross deferred tax assets	24,000	25,000
Valuation allowance	0
Net deferred tax assets	24,000	25,000
Depreciation	(157,000)	(164,000)
Intangibles	(52,000)	(66,000)
Other	0
Gross deferred tax liabilities	(209,000)	(230,000)
Net deferred tax liability	185,000	205,000
Worldwide [Member]
Income Tax [Line Items]
Credits	3,501,000	3,530,000
NOLs	2,998,000	3,260,000
Stock compensation	202,000	203,000
Accruals	310,000	209,000
Other	126,000	109,000
Gross deferred tax assets	7,137,000	7,311,000
Valuation allowance	(1,916,000)	(1,777,000)
Net deferred tax assets	5,221,000	5,534,000
Depreciation	(1,351,000)	(1,332,000)
Intangibles	(11,000)	(73,000)
Other	0
Gross deferred tax liabilities	(1,362,000)	(1,405,000)
Net deferred tax asset (liability)	$ 3,859,000	$ 4,129,000