XML 47 R32.htm IDEA: XBRL DOCUMENT v3.7.0.1
Employee Stock-Based Compensation - Restricted Stock Unit Valuation (Detail) - Market and Service Condition Based Restricted Stock Unit Grants
6 Months Ended
Jun. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Expected volatility (company) 73.70%
Expected volatility (peer group median) 33.80%
Correlation between the company and peer group median 0.33
Expected dividend yield 0.00%
Risk-free rate 1.50%