Summary of Significant Accounting Policies - Narrative (Details) $ / shares in Units, $ in Thousands		3 Months Ended	6 Months Ended
	Sep. 10, 2018 USD ($) extension_period $ / shares	Sep. 30, 2018 USD ($) $ / shares	Sep. 30, 2018 USD ($) Sales_channels $ / shares	Apr. 02, 2018 USD ($)	Apr. 01, 2018 USD ($) $ / shares
New Accounting Pronouncement, Early Adoption [Line Items]
Common Stock, par value (in dollars per share) | $ / shares	$ 0.001	$ 0.001	$ 0.001		$ 0.001
Per share merger consideration (in dollars per share) | $ / shares	$ 49.00
Number of merger extension periods | extension_period	2
Merger agreement, extension period			3 months
Required payment by either party for termination or merger agreement	$ 166,400
Transaction-related costs		$ 3,900
Number of channels that products are sold through | Sales_channels			3
Cumulative-effect adjustment to accumulated deficit		$ 248,906	$ 248,906		$ 301,155
Accounting Standards Update 2016-16
New Accounting Pronouncement, Early Adoption [Line Items]
Cumulative-effect adjustment to accumulated deficit				$ 13,900