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Stockholders' Equity - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Oct. 20, 2020
May 22, 2018
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Stockholders Equity [Line Items]          
Preferred stock share authorized     50,000,000.0    
Preferred stock share par value     $ 0.0001    
Net proceeds from issuance of common stock and exercise of overallotment     $ 14,249 $ 344 $ 57,041
Repurchase of Common Stock       $ 800 $ 200
Follow-on Public Offering [Member]          
Stockholders Equity [Line Items]          
Common stock, issued and sold 3,750,000 4,057,500      
Common stock issued price per share $ 4.00 $ 15.00      
Net proceeds from issuance of common stock and exercise of overallotment $ 14,000 $ 57,000      
Underwriting discounts and commissions   3,200      
Offering expenses   $ 700      
After deduction of placement, agent fees and other offering expenses $ 1,000        
Follow-on Public Offering [Member] | Cellectis [Member]          
Stockholders Equity [Line Items]          
Common stock, issued and sold 1,250,000 550,000 1,250,000   550,000
Common stock issued price per share     $ 4.00   $ 15.00
Net proceeds from issuance of common stock and exercise of overallotment $ 5,000 $ 8,300      
Outstanding obligation paid to parent $ 14,000 $ 57,000      
Underwriters Option to Purchase Additional Shares [Member]          
Stockholders Equity [Line Items]          
Common stock, issued and sold   457,500