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Investments - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020	Jul. 13, 2020
Schedule Of Available For Sale Securities [Line Items]
Realized gains (losses)		$ 0	$ 0	$ 0	$ 0
Short-term investments						$ 0
Proceeds from investment security transaction				$ 269,000
Debt Security
Schedule Of Available For Sale Securities [Line Items]
Proceeds from investment security transaction	$ 300,000
Additional cash compensation to be received based on conditions met	2,400,000
Repurchase price of bond if conditions not met	$ 1.00
Gain on investment		$ 300,000
Debt Security \| Third in Line lien on Assets \| International Seismic Marine
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value							$ 13,000,000.0
Unpaid invoices and later fees owed by customer							$ 13,000,000.0
Debt instrument, description				The bond is secured by a third in line lien on the assets owned by the customer and has an 8% interest rate with bi-annual interest and possible principal payments based on available excess cash flows. Interest payments can be made either in cash or in-kind payments in the form of additional debt security. In-kind interest payments require an 8.8% interest rate.
Investment interest rate							8.00%
In-kind payments, interest rate							8.80%
Maturity date							Jul. 13, 2022
Minimum
Schedule Of Available For Sale Securities [Line Items]
Short-term investments maturity date		Sep. 30, 2021		Sep. 30, 2021
Maximum
Schedule Of Available For Sale Securities [Line Items]
Short-term investments maturity date		May 31, 2022		May 31, 2022