Revenue Recognition - Additional Information (Details) - USD ($)	3 Months Ended				12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Unbilled receivables	$ 4,263,000
Deferred contract costs	0				$ 0
Revenue	26,722,000			$ 9,083,000
Cost of revenue recognized from deferred contract cost	0			0
Cost of revenue	21,735,000			15,208,000
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			$ 0
Partially financed product sale			12,500,000
Cost of revenue			$ 0
Payments received from customer	$ 5,300,000
Deferred Revenue and Other Liabilities
Disaggregation Of Revenue [Line Items]
Deferred contract liabilities	0				200,000
Deferred Contract Liability
Disaggregation Of Revenue [Line Items]
Revenue	200,000			$ 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	8,800,000				$ 300,000
Unbilled receivables	4,300,000
Revenue for unsatisfied performance obligations	$ 1,600,000