CONSOLIDATED STATEMENTS OF CASH FLOW (Parenthetical) $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($)
CONSOLIDATED STATEMENTS OF CASH FLOWS
Proceeds from issuance of common stock, net, from related parties	$ 30,850

The cash inflow from the additional capital contribution to the entity from related parties.

No definition available.

Name:	crvs_ProceedsFromIssuanceOfCommonStockRelatedParty
Namespace Prefix:	crvs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration