POWER OF ATTORNEY


KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and
appoints CRAIG L. SLUTZKIN as his true and lawful attorney-in-fact and agent for
him and in his name, place and stead, in any and all capacities, to sign any and
all documents relating to any and all Securities and Exchange Commission filings
which may be required, granting unto said attorney-in-fact and agent full power
and authority to do and perform each and every act and thing requisite and
necessary to be done in and about the premises, as fully to all intents and
purposes as he might or could do in person, thereby ratifying and confirming all
that said attorney-in-fact may lawfully do or cause to be done by virtue hereof.


This power shall continue in effect until terminated in writing.


By:	 /s/ Daniel Becker
	Daniel Becker


Dated: September 4, 2018