Annual report pursuant to Section 13 and 15(d)

Equity Compensation - Fair Value for Options Granted under Employee Stock Purchase Plan (Details)

v3.10.0.1
Equity Compensation - Fair Value for Options Granted under Employee Stock Purchase Plan (Details) - Employee Stock
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]      
Risk-free Interest Rate 2.60% 1.31% 0.63%
Dividend Yield 0.00% 0.00% 0.00%
Volatility Factor 0.33% 0.26% 0.45%
Expected Life in Years 1 year 1 year 1 year