Commitments and Contingencies - Operating Lease Commitments (Details)	1 Months Ended	12 Months Ended
	Mar. 31, 2019 ft² item	Sep. 30, 2017 ft² item
Lease Arrangement, Indianapolis, Indiana, August 2017 to September 2023
Property Subject to or Available for Operating Lease [Line Items]
Area leased (in sq. ft.)		85,000
Lease term		6 years
Lease renewal term		5 years
Number of renewal terms | item		3
Lease Arrangement, Indianapolis, Indiana, March 2019 to September 2023 | Scenario, Forecast
Property Subject to or Available for Operating Lease [Line Items]
Area leased (in sq. ft.)	13,000
Lease term	4 years 6 months
Lease renewal term	5 years
Number of renewal terms | item	3
Lease Arrangement, Fremont, California
Property Subject to or Available for Operating Lease [Line Items]
Area leased (in sq. ft.)		45,000
Lease renewal term		5 years
Number of renewal terms | item		2
Lease Arrangement, Manchester, United Kingdom
Property Subject to or Available for Operating Lease [Line Items]
Area leased (in sq. ft.)		45,000
Lease renewal term		5 years