Quarterly report pursuant to Section 13 or 15(d)

Notes Payable and Line of Credit - Additional Information (Details)

v3.19.3
Notes Payable and Line of Credit - Additional Information (Details) - USD ($)
1 Months Ended 9 Months Ended
Jan. 31, 2018
Dec. 31, 2015
Sep. 30, 2019
Dec. 31, 2018
Dec. 31, 2017
Silicon Valley Bank | Revolving Credit Facility          
Line Of Credit Facility [Line Items]          
Line of credit facility allowable amount $ 10,000,000       $ 3,000,000
Line of credit     $ 0 $ 0  
Line of credit facility borrowing base limitation percentage of eligible receivables 80.00%        
Liquidity ratio 125.00%        
Interest rate fixed percentage $ 3,000        
Line of credit facility floating rate not met 2.00%   5.00%    
Line of credit facility maturity date     Jan. 31, 2020    
Silicon Valley Bank | Revolving Credit Facility | The Wall Street Journal Prime Rate          
Line Of Credit Facility [Line Items]          
Basis spread on variable interest rate 1.00%   5.00%    
Line Of Credit Facility Interest Rate Description     The Company will be required to pay interest on borrowings outstanding, if any, under the revolving line of credit at a floating rate per annum equal to 1% above the Wall Street Journal prime rate (5.0% as of September 30, 2019) (or, if unavailable, the Silicon Valley Bank prime rate) on a monthly basis, so long as the Company maintains a liquidity ratio of cash and cash equivalents plus accounts receivable to outstanding debt under the Amended Loan Agreement minus deferred revenue of 1.25 to 1.00. If this liquidity ratio is not met, the Company will be subject to a minimum interest charge of $3,000 per month and borrowings outstanding, if any, under the revolving line of credit will accrue interest at a floating rate per annum equal to 2% above the Wall Street Journal prime rate (5.0% as of September 30, 2019) (or, if unavailable the Silicon Valley Bank prime rate) on a monthly basis. Prior to the amendment in January 2018, the revolving line of credit bore interest rate at the U.S. prime rate plus 1.25%. The revolving line of credit matures on January 31, 2020.    
Silicon Valley Bank | Revolving Credit Facility | Prime Rate          
Line Of Credit Facility [Line Items]          
Liquidity ratio 125.00%        
Silicon Valley Bank | Revolving Credit Facility | U.S. Prime Rate          
Line Of Credit Facility [Line Items]          
Basis spread on variable interest rate 1.25%        
Loan Agreement With Silicon Valley Bank          
Line Of Credit Facility [Line Items]          
Loan agreement amount   $ 4,000,000      
Term of payments   36 months      
Date of maturity   Dec. 01, 2018      
Interest rate fixed percentage   5.00%