Commitments and Contingencies - Summary of Northrop Agreement Activity (Details) - Northrop $ in Millions	Mar. 31, 2020 USD ($)
Contingencies And Commitments [Line Items]
Total reimbursable costs under the Northrop Agreement	$ 189.7
Amount reimbursed to the Company through March 31, 2020	(138.7)
Receivable from Northrop included in the unaudited balance sheet at March 31, 2020	$ 51.0