Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Derivative Contingently Issuable Warrant liabilities (Detail)

v3.6.0.2
Fair Value Measurements - Derivative Contingently Issuable Warrant liabilities (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Additions $ 19,089 $ 289
Avenue [Member] | Contingently Issuable Warrants [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 114  
Additions 0  
Change in fair value 188  
Fair value at end of period: 302 114
Mustang [Member] | Contingently Issuable Warrants [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 0  
Additions 634  
Change in fair value 159  
Issuance of Warrants (793)  
Fair value at end of period: 0 0
Mustang [Member] | Warrant [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 0  
Additions 12  
Change in fair value 0  
Fair value at end of period: 12 0
Checkpoint [Member] | Contingently Issuable Warrants [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 0 0
Additions   175
Change in fair value   438
Issuance of Warrants   (613)
Fair value at end of period:   0
Helocyte [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 0  
Additions 428  
Change in fair value (261)  
Fair value at end of period: $ 167 $ 0