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Commitment and Contingencies - Additional Information (Detail)
$ in Thousands
 1 Months Ended 12 Months Ended
Feb. 28, 2013
USD ($)
ft²
Sep. 30, 2006
USD ($)
ft²
$ / ft²
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Jun. 30, 2012
USD ($)
Commitments And Contingencies [Line Items]            
Restricted cash     $ 7,254 $ 7,254    
FibroGen, Inc. [Member]            
Commitments And Contingencies [Line Items]            
Land subject to leases | ft²   234,249        
Initial term of lease contract   15 years        
Restricted cash   $ 7,254        
Description of lessee leasing arrangements, operating leases     The agreement included an expansion option to occupy part of an adjacent building within 31 months of the lease commencement date of November 20, 2008.      
Lease incentive receivable from land lord through expansion option not used           $ 5,000
Percentage of construction costs for tenant improvement   60.00%        
Tenant improvement price per square foot of rental space | $ / ft²   140.50        
Tenant improvements allowance of rental space   $ 32,500        
Cost of construction capitalized   50,800        
Reimbursements from landlord for tenant improvements   $ 32,500        
FibroGen, Inc. [Member] | South San Francisco [Member]            
Commitments And Contingencies [Line Items]            
Land subject to sublease | ft²   106,000        
Lease and sublease termination date   Feb. 28, 2015        
FibroGen China [Member]            
Commitments And Contingencies [Line Items]            
Land subject to leases | ft² 4,820          
Initial term of lease contract 8 years          
Percentage of construction costs for tenant improvement 100.00%          
Cost of construction capitalized $ 3,100          
Reimbursements from landlord for tenant improvements $ 500          
Lease starting date Feb. 01, 2013          
Rent expenses for leased facilities     $ 2,700 2,900 $ 3,000  
Sublease income received     $ 3,400 $ 5,000 $ 4,500