Revenue - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020
Capitalized Contract Cost [Line Items]
Current contract assets	$ 2,000		$ 2,000		$ 1,000
Non-current contract assets	0		0		0
Current contract liabilities	1,402		1,402		947
Non-current contract liabilities	100		100		200
Revenue recognized included in contract liabilities			500
Current capitalized costs	106		106		130
Non-current capitalized costs	0		0
Incremental costs amortized	84	$ 84	171	$ 162
Impairment related to costs capitalized	$ 0		$ 0
Payment terms			30 days
Practical Expedient, Incremental Costs			true
Remaining Performance Obligation, Optional Exemption			true
Minimum
Capitalized Contract Cost [Line Items]
Amortization Period	3 years		3 years
Maximum
Capitalized Contract Cost [Line Items]
Amortization Period	6 years		6 years
Europe | Maximum
Capitalized Contract Cost [Line Items]
Payment terms			90 days
TS
Capitalized Contract Cost [Line Items]
Current capitalized costs	$ 13		$ 13		13
Non-current capitalized costs	16		16		$ 22
Incremental costs amortized	$ 3	$ 3	6	$ 6
Impairment related to costs capitalized			$ 0