n/a

No definition available.

Name:	crvs_RelatedPartyStockTransactionsAbstract
Namespace Prefix:	crvs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate value of stock issued to related parties in public offerings.

+ References

No definition available.

+ Details

Name:	crvs_StockIssuedRelatedPartyAggregateValue
Namespace Prefix:	crvs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

The cash inflow associated with the amount received from entity's first offering of stock to the public.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceInitialPublicOffering
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesIssuedPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=crvs_FMRLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=crvs_OrbimedAdvisorsLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=crvs_NovoHoldingsAsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=crvs_AdamsStreetPartnersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_DirectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_OverAllotmentOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Related Party Transaction (Details) - USD ($)			1 Months Ended	3 Months Ended
Related Party Transaction (Details) - USD ($)	Apr. 26, 2016	Mar. 29, 2016	Mar. 31, 2018	Mar. 31, 2018
Public Offerings
Proceeds from sale of stock				$ 64,877,000
FMR LLC
Public Offerings
Number of Share of Common Stock issued			1,176,470
Owners of More Than 5% of Our Common Stock or Board of Directors
Aggregate Purchase Price			$ 9,999,995
Orbimed Advisors LLC
Public Offerings
Number of Share of Common Stock issued			588,235
Owners of More Than 5% of Our Common Stock or Board of Directors
Aggregate Purchase Price			$ 4,999,998
Novo Holdings A/S
Public Offerings
Number of Share of Common Stock issued			1,176,470
Owners of More Than 5% of Our Common Stock or Board of Directors
Aggregate Purchase Price			$ 9,999,995
Adams Street Partners
Public Offerings
Number of Share of Common Stock issued			588,235
Owners of More Than 5% of Our Common Stock or Board of Directors
Aggregate Purchase Price			$ 4,999,998
Director
Public Offerings
Number of Share of Common Stock issued			100,000
Owners of More Than 5% of Our Common Stock or Board of Directors
Aggregate Purchase Price			$ 850,000
IPO
Public Offerings
Share offering price		$ 15.00
Number of Share of Common Stock issued		4,700,000
Net proceeds from IPO	$ 70,600,000
Over-Allotment Option
Public Offerings
Share offering price	$ 15.00
Number of Share of Common Stock issued	502,618		1,058,823