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Stockholders' Equity - Additional Information - Employee Stock Purchase Plan (Detail) - USD ($)
 12 Months Ended
Nov. 14, 2019
May 14, 2019
Nov. 16, 2018
May 16, 2018
Dec. 31, 2019
Dec. 31, 2018
Schedule Of Stockholders Equity [Line Items]            
Employee stock purchase plan expense         $ 31,848 $ 17,738
Shares issued for Employee Stock Purchase Plan options, Value         $ 70,668 $ 40,380
Common Stock [Member]            
Schedule Of Stockholders Equity [Line Items]            
Shares issued for Employee Stock Purchase Plan options, Shares         44,035 26,415
Shares issued for Employee Stock Purchase Plan options, Value         $ 44 $ 27
2014 Employee Stock Purchase Plan [Member] | Common Stock [Member]            
Schedule Of Stockholders Equity [Line Items]            
Shares issued for Employee Stock Purchase Plan options, Shares 22,752 21,283 15,487 10,928 44,035 26,415
Shares issued for Employee Stock Purchase Plan options, Value $ 40,999 $ 29,669 $ 21,984 $ 18,396 $ 70,668 $ 40,380