XML 96 R73.htm IDEA: XBRL DOCUMENT v3.10.0.1
Subsequent Events - Additional Information (Detail) - Office Space [Member]
$ in Millions
 1 Months Ended 3 Months Ended
Jan. 17, 2018
USD ($)
ft²
Option
Aug. 31, 2015
Mar. 31, 2018
Subsequent Event [Line Items]      
Term of lease   5 years  
Lease renewal term   5 years  
Lease Agreements [Member] | Cambridge, Massachusetts [Member] | U.S. REIF Central Plaza Massachusetts, LLC [Memebr]      
Subsequent Event [Line Items]      
Area of office space | ft² 7,800    
Term of lease 7 years    
Lease expiration date Dec. 01, 2018    
Lease renewal term 5 years    
Number of renewal options | Option 2    
Operating lease, option to extend the Company has two consecutive options to extend the Lease Term for an additional period of five years (the “Option Terms”), subject to certain conditions, upon notice to the Landlord.   the Company has two consecutive options to extend the Lease Term for an additional period of five years (the “Option Terms”), subject to certain conditions, upon notice to the Landlord.
Operating leases annual base rent initial $ 0.5    
Operating leases annual base rent final $ 0.6    
Operating lease percentage of annual base rent 100.00%