Commitments and Contingencies - Summary of Northrop Agreement Activity (Details) - Northrop $ in Millions	Jun. 30, 2020 USD ($)
Contingencies And Commitments [Line Items]
Total reimbursable costs under the Northrop Agreement	$ 189.7
Amount reimbursed to the Company through June 30, 2020	(140.2)
Receivable from Northrop included in the unaudited balance sheet at June 30, 2020	$ 49.5