Annual report pursuant to Section 13 and 15(d)

Income Taxes - Summary of Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision (Detail)

v2.4.1.9
Income Taxes - Summary of Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Income Tax Disclosure [Abstract]    
Expected income tax benefit at federal statutory tax rate $ (10,851)us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate $ (3,424)us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
Net operating loss adjustments (1,703)cyma_EffectiveIncomeTaxRateReconciliationNetOperatingLossAdjustments 4,441cyma_EffectiveIncomeTaxRateReconciliationNetOperatingLossAdjustments
Change in valuation allowance 11,189us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance (1,757)us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance
State income taxes, net of federal benefit (783)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes 583us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
Permanent items 2,595cyma_IncomeTaxReconciliationEffectOfPermanentItems 555cyma_IncomeTaxReconciliationEffectOfPermanentItems
Research credits (446)us-gaap_IncomeTaxReconciliationTaxCreditsResearch (396)us-gaap_IncomeTaxReconciliationTaxCreditsResearch
Other, net (1)us-gaap_IncomeTaxReconciliationOtherReconcilingItems (2)us-gaap_IncomeTaxReconciliationOtherReconcilingItems
Income tax (benefit) expense $ 0us-gaap_IncomeTaxExpenseBenefit $ 0us-gaap_IncomeTaxExpenseBenefit