Annual report pursuant to Section 13 and 15(d)

Collaboration and License Agreements - Additional Information (Detail)

v2.4.1.9
Collaboration and License Agreements - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Jun. 30, 1998
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]      
License agreement date Jun. 30, 1998    
Monthly license fees     $ 2,000cyma_MonthlyLicenseFees
Potential future development payments     800,000cyma_LicenseAndCollaborationAgreementsPotentialPaymentsForDevelopmentMilestones
Development payment 0cyma_DevelopmentPayment 0cyma_DevelopmentPayment  
Royalty payment 0us-gaap_PaymentsForRoyalties 0us-gaap_PaymentsForRoyalties  
Janssen Pharmaceutical NV [Member]      
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]      
Collaboration agreement date Jun. 30, 2006    
Payments made under agreement 0cyma_PaymentsMadeUnderLicenseAgreement
/ dei_LegalEntityAxis
= cyma_JanssenPharmaceuticalNVMember
0cyma_PaymentsMadeUnderLicenseAgreement
/ dei_LegalEntityAxis
= cyma_JanssenPharmaceuticalNVMember
 
Royalties received 0us-gaap_ProceedsFromRoyaltiesReceived
/ dei_LegalEntityAxis
= cyma_JanssenPharmaceuticalNVMember
0us-gaap_ProceedsFromRoyaltiesReceived
/ dei_LegalEntityAxis
= cyma_JanssenPharmaceuticalNVMember
 
Janssen Pharmaceutical NV [Member] | Maximum [Member]      
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]      
Percentage of royalty on net sales 8.00%cyma_RoyaltyPercentageBasedOnNetSales
/ dei_LegalEntityAxis
= cyma_JanssenPharmaceuticalNVMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
   
Janssen Pharmaceuticals, Inc. [Member]      
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]      
License agreement date Jun. 30, 2010    
Number of development and license agreements 2cyma_NumberOfDevelopmentAndLicenseAgreements
/ dei_LegalEntityAxis
= cyma_JanssenPharmaceuticalsIncMember
   
Contingent payment eligible to receive on development and commercial events $ 228,000,000cyma_ContingentPaymentsReceivableBasedOnDevelopmentEvents
/ dei_LegalEntityAxis
= cyma_JanssenPharmaceuticalsIncMember