XML 45 R40.htm IDEA: XBRL DOCUMENT v2.4.1.9
Stock-Based Compensation (Details 3) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Unrecognized stock-based compensation expense  
Unrecognized stock compensation expense $ 16,013us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Weighted average remaining period 2 years 10 months 13 days
Common stock options  
Unrecognized stock-based compensation expense  
Unrecognized stock compensation expense 13,468us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= snta_EmployeeAndDirectorsStockOptionsMember
Weighted average remaining period 2 years 9 months 7 days
Restricted stock  
Unrecognized stock-based compensation expense  
Unrecognized stock compensation expense $ 2,545us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Weighted average remaining period 3 years 4 months 21 days