Summary of Significant Accounting Policies - Recent Accounting Pronouncements - Disaggregation of Revenue (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Revenues	$ 43,701,000	$ 40,681,000
United States [Member]
Revenues	34,421,000
Asia [Member]
Revenues	3,206,000	3,017,000
Europe [Member]
Revenues	5,167,000	6,486,000
Other [Member]
Revenues	907,000
Optics [Member]
Revenues	23,250,000	23,053,000
Optics [Member] \| United States [Member]
Revenues	14,916,000
Optics [Member] \| Asia [Member]
Revenues	3,172,000
Optics [Member] \| Europe [Member]
Revenues	4,916,000
Optics [Member] \| Other [Member]
Revenues	246,000
Innovation and Development [Member]
Revenues	20,451,000	$ 17,628,000
Innovation and Development [Member] \| United States [Member]
Revenues	19,505,000
Innovation and Development [Member] \| Asia [Member]
Revenues	34,000
Innovation and Development [Member] \| Europe [Member]
Revenues	251,000
Innovation and Development [Member] \| Other [Member]
Revenues	661,000
Goods/services transferred over time [Member]
Revenues	22,166,000
Goods/services transferred over time [Member] \| Optics [Member]
Revenues	2,326,000
Goods/services transferred over time [Member] \| Innovation and Development [Member]
Revenues	19,840,000
Goods transferred at a point in time [Member]
Revenues	21,535,000
Goods transferred at a point in time [Member] \| Optics [Member]
Revenues	20,924,000
Goods transferred at a point in time [Member] \| Innovation and Development [Member]
Revenues	611,000
Optical components [Member]
Revenues	23,057,000
Optical components [Member] \| Optics [Member]
Revenues	23,057,000
Optical components [Member] \| Innovation and Development [Member]
Revenues	0
Contract research [Member]
Revenues	19,785,000
Contract research [Member] \| Optics [Member]
Revenues	0
Contract research [Member] \| Innovation and Development [Member]
Revenues	19,785,000
Other products and services [Member]
Revenues	859,000
Other products and services [Member] \| Optics [Member]
Revenues	193,000
Other products and services [Member] \| Innovation and Development [Member]
Revenues	666,000
U.S. government revenue [Member]
Revenues	19,051,000
U.S. government revenue [Member] \| Optics [Member]
Revenues	114,000
U.S. government revenue [Member] \| Innovation and Development [Member]
Revenues	18,937,000
U.S. commercial revenue [Member]
Revenues	15,441,000
U.S. commercial revenue [Member] \| Optics [Member]
Revenues	14,873,000
U.S. commercial revenue [Member] \| Innovation and Development [Member]
Revenues	568,000
Foreign commercial and other revenue [Member]
Revenues	9,209,000
Foreign commercial and other revenue [Member] \| Optics [Member]
Revenues	8,263,000
Foreign commercial and other revenue [Member] \| Innovation and Development [Member]
Revenues	946,000
Firm-fixed price [Member]
Revenues	25,516,000
Firm-fixed price [Member] \| Optics [Member]
Revenues	23,250,000
Firm-fixed price [Member] \| Innovation and Development [Member]
Revenues	2,266,000
Non-Firm Fixed price [Member]
Revenues	18,185,000
Non-Firm Fixed price [Member] \| Optics [Member]
Revenues	0
Non-Firm Fixed price [Member] \| Innovation and Development [Member]
Revenues	$ 18,185,000

DYNASIL CORP OF AMERICA 10-K