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Summary of Significant Accounting Policies - Additional Information (Detail) - shares
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Accounting Policies [Abstract]        
Antidilutive securities excluded from computation of earnings per share, amount 587,819 347,611 587,819 347,611