Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Available-for-sale securities (Details)

v3.7.0.1
Summary of Significant Accounting Policies - Available-for-sale securities (Details)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2017
USD ($)
Jun. 30, 2017
USD ($)
security
Available-for-sale securities    
Gross Unrealized Losses $ 1,296 $ 1,296
Aggregate estimated Fair Value 82,074 82,074
Realized gains or losses 0 $ 0
Number of Available for Sale Securities | security   37
Cash equivalents    
Available-for-sale securities    
Amortized cost 2,052 $ 2,052
Gross Unrealized Losses 63 63
Foreign currency translation adjustment 62 62
Aggregate estimated Fair Value 2,051 2,051
Marketable securities    
Available-for-sale securities    
Amortized cost 80,096 80,096
Gross Unrealized Losses 1,233 1,233
Foreign currency translation adjustment 1,160 1,160
Aggregate estimated Fair Value 80,023 80,023
Corporate Debt Securities Maturity Period One Year or Less    
Available-for-sale securities    
Gross Unrealized Losses 0 0
Corporate Debt Securities Maturity Period Less Than Three Months | Cash equivalents    
Available-for-sale securities    
Amortized cost 2,052 2,052
Gross Unrealized Losses 63 63
Foreign currency translation adjustment 62 62
Aggregate estimated Fair Value 2,051 2,051
Corporate Debt Securities Maturity Period Three Months To One Year | Marketable securities    
Available-for-sale securities    
Amortized cost 73,601 73,601
Gross Unrealized Losses 1,132 1,132
Foreign currency translation adjustment 1,068 1,068
Aggregate estimated Fair Value 73,537 73,537
Corporate Debt Securities Maturity Period One Year To Two Years | Marketable securities    
Available-for-sale securities    
Amortized cost 6,495 6,495
Gross Unrealized Losses 101 101
Foreign currency translation adjustment 92 92
Aggregate estimated Fair Value $ 6,486 $ 6,486
Minimum | Corporate Debt Securities Maturity Period Three Months To One Year | Marketable securities    
Available-for-sale securities    
Available For Sale Securities Debt Maturity Period   3 months
Minimum | Corporate Debt Securities Maturity Period One Year To Two Years | Marketable securities    
Available-for-sale securities    
Available For Sale Securities Debt Maturity Period   1 year
Maximum    
Available-for-sale securities    
Available For Sale Securities Debt Maturity Period   1 year
Maximum | Corporate Debt Securities Maturity Period Three Months To One Year | Marketable securities    
Available-for-sale securities    
Available For Sale Securities Debt Maturity Period   1 year
Maximum | Corporate Debt Securities Maturity Period One Year To Two Years | Marketable securities    
Available-for-sale securities    
Available For Sale Securities Debt Maturity Period   2 years