Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v2.4.1.9
Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Product Information [Line Items]    
Proceeds from sale of common stock $ 25,430,000us-gaap_ProceedsFromIssuanceOrSaleOfEquity $ 26,514,000us-gaap_ProceedsFromIssuanceOrSaleOfEquity
Cash and cash equivalents, maturity description 90 days or less  
Short-term contractual maturities 1 year  
Restricted cash 100,000us-gaap_RestrictedCashAndCashEquivalents 155,000us-gaap_RestrictedCashAndCashEquivalents
Impairment losses 0us-gaap_AssetImpairmentCharges 0us-gaap_AssetImpairmentCharges
Interest or penalties related to income taxes 0us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense 0us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Warrants, Exercise price of $5.75 per share [Member]    
Product Information [Line Items]    
Proceeds from sale of common stock $ 3,000,000us-gaap_ProceedsFromIssuanceOrSaleOfEquity
/ us-gaap_ClassOfWarrantOrRightAxis
= cyma_WarrantsOneMember
 
Minimum [Member]    
Product Information [Line Items]    
Property and equipment, estimated useful lives 3 years  
Maximum [Member]    
Product Information [Line Items]    
Property and equipment, estimated useful lives 7 years