Commitments and Contingencies - Contractual Obligations (Details)	2 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2018 USD ($) ft²	Mar. 31, 2017 USD ($)
Property Subject to or Available for Operating Lease [Line Items]
2019		$ 1,347,000
2020		2,009,000
2021		2,063,000
2022		2,127,000
2023		2,200,000
Thereafter		7,650,000
Total minimum operating lease payments		17,396,000
Rent expense	$ 0	$ 900,000	$ 300,000
Brisbane, California Office Space [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area leased (in sq ft) | ft²		40,232
Extension term		7 years