Subsequent Events	3 Months Ended
Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	18. Subsequent Events On April 27, 2022, the European Commission granted marketing authorization to difelikefalin injection under the brand name Kapruvia® (difelikefalin), or Kapruvia, for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adult hemodialysis patients. The marketing authorization approves Kapruvia for use in all member states of the European Union, as well as Iceland, Liechtenstein and Norway. The Company expects commercial launch of Kapruvia in these markets in the second half of 2022. As a result of the European Commission’s regulatory approval of Kapruvia in April 2022, the Company achieved a $15,000 regulatory milestone payment from VFMCRP under the VFMCRP Agreement, which will be recorded as license and milestone fees revenue in the second quarter of 2022.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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