Commitments and Contingencies - Additional Information (Details)	6 Months Ended
Jun. 30, 2019
Maximum
Commitments And Contingencies [Line Items]
Agreement termination notice period	1 year

Line items represent commitments and contingencies.

No definition available.

Name:	dtil_CommitmentsAndContingenciesLineItems
Namespace Prefix:	dtil_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration