Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.10.0.1
Stockholders' Equity - Additional Information (Detail)
$ in Thousands
 1 Months Ended 12 Months Ended
Jun. 30, 2018
USD ($)
shares
Jan. 31, 2018
USD ($)
shares
Dec. 31, 2017
USD ($)
shares
Jan. 31, 2017
USD ($)
shares
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Mar. 31, 2018
USD ($)
shares
Jun. 30, 2017
shares
Mar. 31, 2017
shares
Class of Stock [Line Items]                    
Option to purchase additional shares of common stock 12,000,000   10,000,000              
Proceeds from sale of common stock, net of fees and commissions | $ $ 115,200   $ 94,800              
Fees and commissions | $ $ 3,600   $ 5,200   $ 4,090 $ 5,707 $ 1,681      
Conversion ratio         1          
Treasury shares retired     1,300,000              
Over-allotment Option                    
Class of Stock [Line Items]                    
Option to purchase additional shares of common stock   1,500,000.0                
Proceeds from sale of common stock, net of fees and commissions | $   $ 14,500                
Fees and commissions | $   $ 500                
Option to purchase shares (up to) 1,800,000   1,500,000              
At-the-Market Program                    
Class of Stock [Line Items]                    
Aggregate sales proceeds (up to) | $         $ 189,700          
Convertible Preferred Stock                    
Class of Stock [Line Items]                    
Convertible preferred stock, shares issued               6,100,000    
Discharge of liability outstanding | $         27,300     $ 22,700    
Amount applied to future services | $               $ 27,300    
TOTAL Delaware Inc                    
Class of Stock [Line Items]                    
Option to purchase additional shares of common stock       35,400,000            
Proceeds from sale of common stock, net of fees and commissions | $       $ 207,000            
Shares exchanged for issue of common stock       46,000,000            
GE Oil & Gas, Inc.                    
Class of Stock [Line Items]                    
Number of shares converted                 5,500,000  
GE Oil & Gas, Inc. | Series A Preferred Stock                    
Class of Stock [Line Items]                    
Number of shares converted                   5,500,000
GE Oil & Gas, Inc. | Series B Preferred Stock                    
Class of Stock [Line Items]                    
Number of shares converted                 5,500,000  
Non-current asset                    
Class of Stock [Line Items]                    
Deferred engineering costs | $         $ 50,000