Equity Investment in Unconsolidated Subsidiary - Additional Information (Details) - USD ($)			9 Months Ended
	Sep. 14, 2021	Nov. 06, 2019	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Schedule Of Equity Method Investments [Line Items]
Common stock, shares outstanding (in shares)			5,280,204		5,272,204
Warrant			2,065,000
LGL Systems Acquisition Holdings Company, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Contribution to fund purchase of private warrants		$ 6,100,000
IronNet [Member]
Schedule Of Equity Method Investments [Line Items]
Common stock, shares outstanding (in shares)	1,572,529
Fair value	$ 65,300,000
Equity losses			$ 59,453,000	$ (200,000)
Cumulative loss on investments			$ 59,175,000
IronNet [Member] | Private Warrants [Member]
Schedule Of Equity Method Investments [Line Items]
Warrant	2,065,000