Equity Method Investments, Investment in Arbutus (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023
Investments [Abstract]
Number of shares acquired (in shares)	767,137,861		760,143,393
Aggregate fair value investment	$ 296,243		$ 304,317
Arbutus Biopharma Corporation [Member]
Investments [Abstract]
Equity method investment ownership percentage	23.00%
Aggregate fair value investment	$ 89,300		$ 117,700
Unrealized gain (losses) on investments	$ (28,400)	$ (10,500)
Closing price of common stock (in dollars per share)	$ 2.3		$ 3.03
Arbutus Biopharma Corporation [Member] | Common Stock [Member]
Investments [Abstract]
Number of shares acquired (in shares)	38,847,462