Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.10.0.1
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Significant Accounting Policies [Line Items]          
Trade accounts receivable $ 0   $ 0   $ 0
Impairment of long-lived assets 0 $ 0 0 $ 0  
Fair value movements between Level 2 and Level 3     0 0  
Cost of revenue 0 0 0 0 0
Interest expense on financing lease obligation 317,000   552,000    
Interest income 245,000   412,000    
Forward Purchase Contracts [Member]          
Significant Accounting Policies [Line Items]          
Asset Derivatives 9,000   9,000   3,000
Liability Derivatives 363,000   363,000   $ 4,000
Level 3 [Member]          
Significant Accounting Policies [Line Items]          
Financial instruments classified as Level 3 $ 0 $ 0 $ 0 $ 0