Revenue Recognition - Additional Information (Details) - USD ($)	3 Months Ended				6 Months Ended		12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Unbilled receivables	$ 2,707,000				$ 2,707,000
Deferred contract costs	0				0		$ 0
Revenue	21,604,000			$ 9,517,000	48,326,000	$ 18,600,000
Cost of revenue	23,045,000			18,002,000	$ 44,780,000	33,210,000
Secured Promissory Note
Disaggregation Of Revenue [Line Items]
Value of notes with customer				$ 10,000,000.0		10,000,000.0
Term of the notes				3 years
Monthly principal and interest payments				$ 300,000
Frequency of payments				monthly	monthly
Product
Disaggregation Of Revenue [Line Items]
Revenue	12,500,000	$ 0
Cost of revenue		$ 0
Partially financed product sale				$ 12,500,000
Payments received from customer					$ 6,100,000
Deferred Revenue and Other Liabilities
Disaggregation Of Revenue [Line Items]
Deferred contract liabilities	0				0		200,000
Deferred Contract Liability
Disaggregation Of Revenue [Line Items]
Revenue	0			0	200,000	0
Cost of revenue	0			$ 0	0	$ 0
U.S. Customs and Border Protection ("CBP")
Disaggregation Of Revenue [Line Items]
Awarded contract amount			$ 10,500,000
Increase in contract amount			$ 300,000
Revenue recognized under the contract					8,900,000		$ 300,000
Unbilled receivables	2,700,000				2,700,000
Revenue for unsatisfied performance obligations	$ 1,300,000				$ 1,300,000