Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Narrative (Details)

v3.20.4
Commitments and Contingencies - Narrative (Details)
1 Months Ended 2 Months Ended 12 Months Ended 24 Months Ended
Jun. 30, 2017
USD ($)
Jun. 30, 2017
USD ($)
Apr. 30, 2017
USD ($)
Dec. 31, 2016
USD ($)
Mar. 01, 2021
USD ($)
ft²
Dec. 31, 2020
USD ($)
ft²
numberOfRenewalOption
security
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2012
USD ($)
Dec. 31, 2012
USD ($)
Apr. 30, 2020
ft²
Jan. 31, 2020
ft²
Long-term Purchase Commitment [Line Items]                        
Number of buildings | security           4            
Area of real estate property (in square feet) | ft²           77,300            
Payments for capital improvements     $ 300,000 $ 400,000                
Finance lease, term of contract     3 years 3 years                
Rent expense               $ 3,200,000        
Sublease Income           $ 55,000 $ 957,000 1,100,000        
Indemnification agreement                        
Long-term Purchase Commitment [Line Items]                        
Accruals for expenses related to indemnification issues           0 0 $ 0        
Fifth Amendment                        
Long-term Purchase Commitment [Line Items]                        
Payments for capital improvements                 $ 3,600,000      
Payments for (proceeds from) tenant allowance                   $ (3,100,000)    
Term Loan [Member]                        
Long-term Purchase Commitment [Line Items]                        
Current borrowing capacity $ 10,000,000.0 $ 10,000,000.0                    
Interest rate, stated percentage 3.75% 3.75%                    
Basis spread on variable rate   0.005%                    
Revolving Credit Facility [Member]                        
Long-term Purchase Commitment [Line Items]                        
Current borrowing capacity $ 5,000,000.0 $ 5,000,000.0                    
Accounts receivable borrowing base percentage 80.00%                      
Interest rate, stated percentage 4.25% 4.25%                    
Revolving Credit Facility [Member] | Prime Rate                        
Long-term Purchase Commitment [Line Items]                        
Basis spread on variable rate   1.00%                    
Demand deposits | Letter of Credit                        
Long-term Purchase Commitment [Line Items]                        
Cash deposit balance           $ 1,100,000 1,100,000          
200-220 Penobscot                        
Long-term Purchase Commitment [Line Items]                        
Area of real estate property (in square feet) | ft²           28,200            
Number of options to extend lease term | numberOfRenewalOption           1            
Renewal term           5 years            
400 Penoscot                        
Long-term Purchase Commitment [Line Items]                        
Area of real estate property (in square feet) | ft²           37,900            
501 Chesapeake                        
Long-term Purchase Commitment [Line Items]                        
Area of real estate property (in square feet) | ft²           11,200            
Number of options to extend lease term | numberOfRenewalOption           1            
Renewal term           5 years            
101 Saginaw                        
Long-term Purchase Commitment [Line Items]                        
Area of real estate property (in square feet) | ft²           29,900            
Sublease                        
Long-term Purchase Commitment [Line Items]                        
Area of real estate property (in square feet) | ft²                     3,400 26,500
Headquarters Redwood City                        
Long-term Purchase Commitment [Line Items]                        
Asset retirement obligations           $ 200,000 $ 200,000          
San Carlos, California | Subsequent Event                        
Long-term Purchase Commitment [Line Items]                        
Area of real estate property (in square feet) | ft²         36,593              
Payments for (proceeds from) tenant allowance         $ 6,300,000