Development and License Agreements - Summary of Amounts Payable and Amounts Receivable from Fresenius (Detail) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Related Party Transactions [Abstract]
Payables to Fresenius	[1]	$ 13,838	$ 8,470
Receivables from Fresenius	[2]	$ 2,380	$ 1,796

[1] Included in “Accounts Payable” and “Accrued Liabilities” in the Company's consolidated balance sheets.

[2] Included in “Prepaid and other current assets” in the Company's consolidated balance sheets.