Amortization period of payments of principal plus interest amounts.

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Debt instrument prepayment fee percentage.

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Interest only period extended.

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Exercise price per share or per unit of warrants or rights outstanding.

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The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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The average effective interest rate during the reporting period.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Percentage of principal amount of debt redeemed.

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Amount, after accumulated amortization, of debt discount.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The cash inflow from issuance of callable preferred stock which is identified as being convertible to another type of financial security at the option of the issuer or the holder.

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The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity.

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Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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Debt - Additional Information (Details) - USD ($)	1 Months Ended					12 Months Ended
Debt - Additional Information (Details) - USD ($)	Mar. 31, 2019	Aug. 31, 2018	Nov. 30, 2017	Oct. 31, 2017	Jan. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Net proceeds from sale of shares						$ 0	$ 17,712,000
Silicon Valley Bank
Debt Instrument [Line Items]
Percentage of final payment on principal amount of refinanced advances	6.00%
Silicon Valley Bank \| Tranche 1, 2, and 3
Debt Instrument [Line Items]
Amortization period of payments of principal plus interest amounts	33 months
Interest rate	6.50%
SVB and WestRiver \| Tranche 1
Debt Instrument [Line Items]
Number of warrants issued (in shares)	37,606
Exercise price of warrant (in usd per share)	$ 4.73
Proceeds from lines of credit	$ 7,500,000
SVB and WestRiver \| Tranche 2
Debt Instrument [Line Items]
Number of warrants issued (in shares)	12,130
Exercise price of warrant (in usd per share)	$ 10.86
SVB and WestRiver \| Tranche 3
Debt Instrument [Line Items]
Number of warrants issued (in shares)	24,262
Exercise price of warrant (in usd per share)	$ 3.88
Term Loan \| Silicon Valley Bank
Debt Instrument [Line Items]
Number of warrants issued (in shares)				49,713
Exercise price of warrant (in usd per share)				$ 9.659
Warrants exercisable date				Oct. 18, 2027
Interest expense						1,100,000	600,000
Line of credit facility, maximum borrowing capacity				$ 7,500,000
Interest only period extended				Dec. 31, 2018
Amortization period of payments of principal plus interest amounts				24 months
Percentage of aggregate principal amount				7.00%
Term Loan \| Silicon Valley Bank \| Tranche A
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				$ 3,500,000
Proceeds from lines of credit			$ 3,500,000
Term Loan \| Silicon Valley Bank \| Tranche B
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				2,000,000
Term Loan \| Silicon Valley Bank \| Tranche C
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				$ 2,000,000
Term Loan \| Silicon Valley Bank \| Prepayment Made Prior To First Anniversary \| Loan and Security Agreement
Debt Instrument [Line Items]
Prepayment fee percentage				3.00%
Term Loan \| Silicon Valley Bank \| Prepayment Made By Second Anniversary \| Loan and Security Agreement
Debt Instrument [Line Items]
Prepayment fee percentage				2.00%
Term Loan \| Silicon Valley Bank \| Prepayment Made After Second Anniversary \| Loan and Security Agreement
Debt Instrument [Line Items]
Prepayment fee percentage				1.00%
Term Loan \| Silicon Valley Bank \| Tranche 2
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 2,500,000.0
Term Loan \| Silicon Valley Bank \| Tranche 3
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	5,000,000.0
Term Loan \| Silicon Valley Bank \| Tranche 1, 2, and 3
Debt Instrument [Line Items]
Debt discount						400,000
Term Loan \| SVB and WestRiver
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	15,000,000.0
Term Loan \| SVB and WestRiver \| Tranche 1
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 7,500,000.0
Series D Redeemable Preferred Stock
Debt Instrument [Line Items]
Sale of stock (in shares)		1,842,959
Sale of stock price per share (in usd per share)		$ 9.659
Net proceeds from sale of shares		$ 17,700,000
Debt converted into shares (in shares)		2,080,209
Series C-1
Debt Instrument [Line Items]
Exercise price of warrant (in usd per share)		$ 0.12
2017 Notes
Debt Instrument [Line Items]
Debt instrument principal amount					$ 14,700,000
Interest rate					8.00%
Proceeds from sale of equity					$ 10,000,000
Debt instrument, redemption price, percentage					80.00%
Debt discount						3,000,000
Interest expense							$ 3,400,000
Prime Rate \| Silicon Valley Bank \| Tranche 1, 2, and 3
Debt Instrument [Line Items]
Interest rate, percentage point added to reference rate	1.00%
Warrant \| Series C-1
Debt Instrument [Line Items]
Number of warrants issued (in shares)		368,582
Warrant \| 2017 Notes
Debt Instrument [Line Items]
Debt discount						$ 1,700,000
Number of warrants issued (in shares)						304,397
Exercise price of warrant (in usd per share)						$ 0.12
Warrants exercisable date						Jan. 31, 2024