XML 67 R36.htm IDEA: XBRL DOCUMENT v3.20.1
Stockholders' Equity - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended
Sep. 30, 2019
Nov. 30, 2018
Aug. 31, 2016
Jan. 31, 2016
Dec. 31, 2012
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Class of Stock [Line Items]                
Net proceeds from sale of common stock $ 271,500,000 $ 298,500,000 $ 215,900,000 $ 281,600,000   $ 3,754,000 $ 4,176,000  
Share of common stock issued 7,187,500 18,602,941 6,969,696 10,344,827 19,000,000      
Value of shares purchased by Baker Entities in public offerings           $ 15,000   $ 15,000
Proceed from sale of stock and warrants         $ 80,500,000      
Common stock sale price per share         $ 4.43      
Expire on December 17, 2019                
Class of Stock [Line Items]                
Warrants issued         500,000      
Warrants issuance price per share         $ 4.42      
Warrant exercise price         $ 0.01      
Issuance of warrant value         $ 2,200,000      
Warrants outstanding         500,000 493,145    
Description of warrant           Per their terms, the warrants to purchase 500,000 shares of common stock, of which 493,145 remained outstanding at March 31, 2020, may not be exercised if the holder’s ownership of the Company’s common stock would exceed 19.99 percent following such exercise.    
Registration Rights Agreement                
Class of Stock [Line Items]                
Expiration period       10 years        
Maximum amount of expense agreed to bear under the agreement       $ 50,000        
Registration Rights Agreement | Baker Brothers Life Sciences L.P.                
Class of Stock [Line Items]                
Value of shares purchased by Baker Entities in public offerings $ 62,500,000 $ 200,000,000.0 $ 43,000,000.0 $ 75,000,000.0        
Option To Purchase Additional Shares                
Class of Stock [Line Items]                
Share of common stock issued 937,500 2,426,470 909,090