Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Warrant Liabilities And Convertible Notes At Fair Value (Detail)

v3.8.0.1
Fair Value Measurements - Warrant Liabilities And Convertible Notes At Fair Value (Detail) - $ / shares
 3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Warrants Issuable [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate   2.20%
Expected dividend yield   0.00%
Expected term in years   3 years 8 months 8 days
Expected volatility   46.13%
Helocyte [Member] | Convertible Debt [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Expected dividend yield 0.00%  
Expected volatility 53.10%  
Helocyte [Member] | Minimum [Member] | Convertible Debt [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 1.96%  
Expected term in years 6 months 29 days  
Helocyte [Member] | Maximum [Member] | Convertible Debt [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 2.21%  
Expected term in years 1 year 8 months 1 day  
Helocyte [Member] | Warrant [Member] | Minimum [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 2.411%  
Expected term in years 3 years 3 months  
Helocyte [Member] | Warrant [Member] | Maximum [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 2.447%  
Expected term in years 3 years 8 months 1 day  
National Warrant Liabilities [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Expected dividend yield 0.00%  
National Warrant Liabilities [Member] | Minimum [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 1.53%  
Expected term in years 5 months 5 days  
Strike price $ 0.01  
Remaining volatility 59.69%  
National Warrant Liabilities [Member] | Maximum [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 2.20%  
Expected term in years 4 years 4 months 6 days  
Strike price $ 10.00  
Remaining volatility 369.19%  
Caelum Convertible Notes [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Expected dividend yield 0.00%  
Expected volatility 53.10%  
Caelum Convertible Notes [Member] | Minimum [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 1.71%  
Expected term in years 2 months 16 days  
Caelum Convertible Notes [Member] | Maximum [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Risk-free interest rate 2.17%  
Expected term in years 1 year 5 months 16 days