Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Detail)

v3.10.0.1
Related-Party Transactions - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Former Member of Board of Directors [Member]        
Related Party Transaction [Line Items]        
Advisory fee paid to related party $ 15,000 $ 15,000 $ 30,000 $ 30,000