Income Taxes - Narrative (Details) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	0.00%	(0.15%)	0.09%
Income tax receivable		$ 1,000	$ 105
Operating Loss Carryforwards [Line Items]
Deferred tax assets valuation allowance		21,367	$ 7,401
Switzerland
Operating Loss Carryforwards [Line Items]
Net operating losses		155,500
Ireland
Operating Loss Carryforwards [Line Items]
Net operating losses		23
United Kingdom
Operating Loss Carryforwards [Line Items]
Net operating losses		6,700
United States | Research and Development Credit Carryforward
Operating Loss Carryforwards [Line Items]
Credit carryforwards		$ 2,900