Annual report pursuant to Section 13 and 15(d)

Financial Instruments Financial Instruments (Details 2)

v3.6.0.2
Financial Instruments Financial Instruments (Details 2) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Amortized Cost Basis $ 93,129 $ 79,800  
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax 0 0  
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax 39 114  
Available-for-sale Securities 93,090 79,686  
Business Combination, Contingent Consideration, Liability     $ 1,700
Money Market Funds [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Amortized Cost Basis 39,181 17,144  
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax 0 0  
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax 0 0  
Available-for-sale Securities 39,181 17,144  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 39,181 17,144  
Available-for-sale Securities, Debt Securities, Current 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Contingent Consideration [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Debt Securities, Current 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 39,181 17,144  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 53,909 62,542  
Available-for-sale Securities, Debt Securities, Current 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Contingent Consideration [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Debt Securities, Current 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 27,993 17,273  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 25,916 45,269  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Debt Securities, Current   395  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 0 0  
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 0 0  
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 93,090 79,686  
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 27,993 17,273  
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 25,916 45,269  
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities 39,181 17,144  
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Business Combination, Contingent Consideration, Liability 375 395  
Corporate Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Amortized Cost Basis 25,923 45,353  
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax 0 0  
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax 7 84  
Available-for-sale Securities 25,916 45,269  
US Government Agencies Debt Securities [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Amortized Cost Basis 28,025 17,303  
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax 0 0  
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax 32 30  
Available-for-sale Securities 27,993 17,273  
Cash and Cash Equivalents [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Amortized Cost Basis 39,181 17,144  
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax 0 0  
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax 0 0  
Available-for-sale Securities 39,181 17,144  
Investments [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale Securities, Amortized Cost Basis 53,948 62,656  
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax 0 0  
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax 39 114  
Available-for-sale Securities $ 53,909 $ 62,542  
Maximum [Member] | Fair Value, Inputs, Level 3 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value Inputs, Discount Rate 1.00% 0.41%