Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Details)

v3.20.1
Summary of Significant Accounting Policies (Details)
$ / shares in Units, $ in Thousands
12 Months Ended 134 Months Ended
Jan. 01, 2019
USD ($)
Dec. 31, 2019
USD ($)
segment
item
$ / shares
Dec. 31, 2018
USD ($)
$ / shares
Dec. 31, 2017
$ / shares
Dec. 31, 2018
USD ($)
Investments          
Marketable securities   $ 3,500 $ 28,590   $ 28,590
Restricted Cash          
Letters of credit   1,300      
Impairment of property and equipment   $ 108     $ 0
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]          
Number of operating segments | segment   1      
Stock-Based Compensation          
Number of stock-based compensation plans | item   2      
Dividend yield   0.00% 0.00% 0.00%  
Basic and diluted net loss per common share calculation:          
Difference between basic and diluted net loss per share of Common Stock (in dollars per share) | $ / shares   $ 0 $ 0 $ 0  
Recent Accounting Standards          
Lease, Practical Expedients, Package [true false] true        
Lease, Practical Expedient, Use of Hindsight [true false] false        
ASU 2016-02          
Recent Accounting Standards          
Right of use assets $ 5,700        
Lease liabilities $ 8,800        
Computer equipment          
Restricted Cash          
Estimated useful life   P3Y      
Laboratory equipment, office equipment, furniture and software          
Restricted Cash          
Estimated useful life   P5Y