Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies (Detail)

v3.19.2
Commitments and Contingencies (Detail)
$ in Thousands
 1 Months Ended 2 Months Ended 3 Months Ended 4 Months Ended 6 Months Ended 24 Months Ended
Apr. 06, 2018
USD ($)
Feb. 28, 2019
plaintiff
claim
Nov. 30, 2015
claim
Jan. 31, 2015
USD ($)
note_offering
claim
underwriter
Jun. 30, 2019
USD ($)
Sep. 30, 2018
claim
Jun. 30, 2019
USD ($)
Dec. 31, 2014
USD ($)
security_offering
firm
underwriter
Dec. 31, 2018
USD ($)
Loss Contingencies [Line Items]                  
Number of prior note offerings | note_offering       3          
Number of firms that underwrote security offerings | firm               9  
Number of security offerings | security_offering               6  
Loss in period         $ 337   $ 1,368    
Loss contingency accrual, product liability         $ 3,413   3,413   $ 9,869
Ladenburg                  
Loss Contingencies [Line Items]                  
Number of underwriters | underwriter               1  
Number of security offerings | security_offering               2  
Securities America                  
Loss Contingencies [Line Items]                  
Number of new claims filed | claim           2      
Number of plaintiffs | plaintiff   14              
Number of unfiled claims | claim   1              
Damages sought by plaintiff $ 5,828           18,000    
Convertible Notes Payable                  
Loss Contingencies [Line Items]                  
Proceeds from issuance Public Offering       $ 300,000          
Common Stock                  
Loss Contingencies [Line Items]                  
Proceeds from issuance Public Offering       $ 1,656,000          
Compensatory damages                  
Loss Contingencies [Line Items]                  
Number of new claims filed | claim     2 2          
Number of underwriters | underwriter       1          
Number of plaintiffs | underwriter       17          
Damages sought by plaintiff               $ 151,000  
Compensatory damages | Ladenburg                  
Loss Contingencies [Line Items]                  
Damages sought by plaintiff               $ 2,900,000  
Compensatory damages | ARCP July 2013 Offering                  
Loss Contingencies [Line Items]                  
Number of underwriters | underwriter       1          
Number of plaintiffs | underwriter       8          
SEC Initiative                  
Loss Contingencies [Line Items]                  
Loss in period             $ 2,149