Quarterly report pursuant to Section 13 or 15(d)

Restructuring Charges - Additional Information (Details)

v3.19.2
Restructuring Charges - Additional Information (Details)
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2019
USD ($)
Facility
Jun. 30, 2018
USD ($)
Jun. 30, 2019
USD ($)
Facility
Jun. 30, 2018
USD ($)
Dec. 31, 2017
Employee
Jan. 31, 2019
Facility
Dec. 31, 2018
USD ($)
Oct. 31, 2018
Facility
Apr. 14, 2018
Facility
Nov. 21, 2017
Facility
Dec. 31, 2016
Facility
Restructuring Cost And Reserve [Line Items]                      
Number of employees terminated | Employee         62            
Operating leases, number of leased facilities | Facility           3   3 3 3  
Restructuring charges (credit)   $ 500,000   $ 500,000              
Lease-related Costs [Member]                      
Restructuring Cost And Reserve [Line Items]                      
Restructuring charges (credit) $ 0 (100,000) $ 0 $ (100,000)              
Lease-related Costs [Member] | Accrued and Other Liabilities [Member]                      
Restructuring Cost And Reserve [Line Items]                      
Combined lease-related liabilities, current portion             $ 1,400,000        
Lease-related Costs [Member] | Long-Term Other Liabilities [Member]                      
Restructuring Cost And Reserve [Line Items]                      
Combined lease-related liabilities, non-current portion             $ 300,000        
Sublease Agreement Commenced on May 1,2018 [Member] | Restructuring Charges [Member]                      
Restructuring Cost And Reserve [Line Items]                      
Sublease loss   $ 600,000                  
Berkeley, California [Member]                      
Restructuring Cost And Reserve [Line Items]                      
Operating leases, number of leased facilities | Facility 2   2               2