Annual report pursuant to Section 13 and 15(d)

Financing Arrangements - Additional Information (Details)

v3.10.0.1
Financing Arrangements - Additional Information (Details)
1 Months Ended 12 Months Ended
Mar. 28, 2017
Installment
$ / shares
shares
Sep. 30, 2017
USD ($)
Jun. 30, 2017
USD ($)
shares
Dec. 31, 2018
USD ($)
Business
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Sep. 27, 2018
USD ($)
Debt Instrument [Line Items]              
Weighted average interest rate         11.54%    
Interest expense on debt         $ 1,100,000 $ 1,200,000  
Amortization of debt issuance costs         132,000 $ 131,000  
Net proceeds from Initial public offering excluding underwriting discounts and commissions     $ 32,400,000   $ 32,426,000    
The March 28, 2017 Preferred stock warrant | Series B-1 Convertible Preferred Stock              
Debt Instrument [Line Items]              
Number of shares called by warrant | shares 76,704   61,363        
Class of warrant, exercise price | $ / shares $ 5.8667            
2015 Term Note | Other Expense, Net              
Debt Instrument [Line Items]              
Loss consisting of prepayment fees and miscellaneous fees   $ 200,000          
Unamortized debt issuance costs written-off   $ 300,000          
Maximum              
Debt Instrument [Line Items]              
Number of shares called by warrant | shares     84,000        
Minimum              
Debt Instrument [Line Items]              
Net proceeds from Initial public offering excluding underwriting discounts and commissions     $ 25,000,000        
Notes Payable | 2015 Term Note              
Debt Instrument [Line Items]              
Debt instrument maturity date Oct. 31, 2020            
Debt instrument number of periodic payment of principal and interest | Installment 36            
Notes Payable | Minimum | 2015 Term Note              
Debt Instrument [Line Items]              
Debt instrument variable rate 11.00%            
LIBOR | Notes Payable | Maximum | 2015 Term Note              
Debt Instrument [Line Items]              
Debt instrument basis spread 7.50%            
LIBOR | Notes Payable | Minimum | 2015 Term Note              
Debt Instrument [Line Items]              
Debt instrument basis spread 2.50%            
Umpqua Credit Agreement              
Debt Instrument [Line Items]              
Credit facility outstanding amount repayment date       Sep. 27, 2020      
Credit facility interest rate description       (1) a base rate, which fluctuates daily and is the greater of (a) the prime rate in effect as of any date of determination and (b) the daily LIBOR rate as of such date of determination plus 1.0% per annum, or (2) a LIBOR rate, which can be for a period of 30, 60 or 90 days at the Company’s option and is equal to the published rate in the Wall Street Journal for such 30-, 60- or 90-day period two business days prior to the commencement of such period, in each case plus 2.0% per annum.      
Credit facility covenant description       Under the Umpqua Credit Agreement, the Company is subject to various negative covenants that limit, subject to certain exclusions, the Company’s ability to incur indebtedness, make loans, invest in or secure the obligations of other parties, pay or declare dividends, make distributions with respect to the Company’s securities, redeem outstanding shares of the Company’s stock, create subsidiaries, materially change the nature of its business, enter into related party transactions, engage in mergers and business combinations, the acquisition or transfer of Company assets outside of the ordinary course of business, grant liens or enter into collateral relationships involving company assets or reincorporate, reorganize or dissolve the Company.      
Credit facility borrowings outstanding       $ 0      
Umpqua Credit Agreement | LIBOR              
Debt Instrument [Line Items]              
Debt instrument basis spread       2.00%      
Period of interest rate option applied on credit facility       30 days      
Period of interest rate option applied on credit facility       60 days      
Period of interest rate option applied on credit facility       90 days      
Number of business days prior to commencement of periods on interest rate | Business       2      
Credit facility variable rate       LIBOR      
Umpqua Credit Agreement | LIBOR | Fluctuating Rate Per Annum              
Debt Instrument [Line Items]              
Debt instrument basis spread       1.00%      
Revolving Facility | Umpqua Credit Agreement              
Debt Instrument [Line Items]              
Credit agreement date       Sep. 27, 2018      
Credit facility maximum borrowing capacity under loan             $ 10,000,000
Revolving Facility | Umpqua Credit Agreement | Maximum              
Debt Instrument [Line Items]              
Increase in credit facility total       $ 25,000,000      
Letter of Credit Subfacility | Umpqua Credit Agreement              
Debt Instrument [Line Items]              
Credit facility maximum borrowing capacity under loan             $ 3,000,000