Geographical Information - Long-lived Assets By Geographic Region (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020
Revenues from External Customers and Long-Lived Assets
Non-current Assets	$ 24,159	$ 33,217
United States
Revenues from External Customers and Long-Lived Assets
Non-current Assets	11,215	19,086
Foreign
Revenues from External Customers and Long-Lived Assets
Non-current Assets	12,944	14,131
Spain
Revenues from External Customers and Long-Lived Assets
Non-current Assets	10,363	0
Netherlands
Revenues from External Customers and Long-Lived Assets
Non-current Assets	2,574	4,778
Estonia
Revenues from External Customers and Long-Lived Assets
Non-current Assets	0	7,408
Mexico
Revenues from External Customers and Long-Lived Assets
Non-current Assets	0	1,845
Other
Revenues from External Customers and Long-Lived Assets
Non-current Assets	$ 7	$ 100