Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation (Additional Information (Detail)

v3.19.1
Basis of Presentation (Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Dec. 31, 2017
Jan. 01, 2019
Summary Of Significant Accounting Policies [Line Items]          
Operating Lease, Liability $ 860,277       $ 994,000
Operating Lease, Liability, Current 533,289   $ 0   533,000
Operating Lease, Liability, Noncurrent 326,988   0   $ 461,000
Net Loss 6,359,761 $ 5,365,650 21,875,713 $ 19,633,502  
Accumulated Deficit $ (124,626,202)   $ (118,266,441)    
Accounts Receivable [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Concentration Risk, Percentage 10.00%        
SATS [Member] | Accounts Receivable [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Concentration Risk, Percentage     38.00%    
Toshiba Japan [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Concentration Risk, Percentage   94.00%      
Engineering Revenues Percentage   18.00%      
Toshiba Japan [Member] | Accounts Receivable [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Concentration Risk, Percentage     32.00%