Subsequent events - Additional Information (Detail) - Subsequent Event - 2019 Equity Plan	Mar. 20, 2019 shares
Subsequent Event [Line Items]
Common stock reserved for issuance	2,426,036
Restricted common stock	2,406,618

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

No definition available.

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration