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Stock-Based Compensation- Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan [Member]
3 Months Ended
Mar. 31, 2017
USD ($)
$ / shares
shares
Employee Stock Purchase Plan ESPP Disclosures [Line Items]  
Options To Purchase Common Stock Shares | shares 54,000
Weighted average fair value of each option | $ / shares $ 10.73
Expected volatility 40.20%
Risk-free weighted average interest rate 0.61%
Vesting Period 6 months
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Payments | $ $ 0