Income Taxes (Deferred Tax Assets (Liabilities) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Jun. 08, 2011
Acquired patents (see also Note 5) $ 0 $ 446    
Liability for accrued employee vacation and severance pay 7 19    
Stock-based compensation 8,104 4,590    
Net operating loss carryforwards 36,605 23,127    
Total gross deferred tax assets 44,716 28,182    
Valuation allowance (44,445) (24,274) (1,231) 0
Deferred tax liability for acquired technology (refer to Note 8): (264) (3,889)    
Net deferred tax assets $ 7 $ 19