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Equity Financings and Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	9 Months Ended		12 Months Ended
	Jun. 03, 2020	Jul. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jul. 22, 2020	Jul. 14, 2020	Jan. 11, 2017
Equity Financing And Warrants [Line Items]
Net proceeds from issuance of common stock			$ 49,644	$ 7,281
Common stock, par value			$ 0.001		$ 0.001
Common stock, shares issued			9,285,624		1,594,070
JonesTrading
Equity Financing And Warrants [Line Items]
Percentage of selling commission per additional shares sold								3.00%
Sales Agreement
Equity Financing And Warrants [Line Items]
Net proceeds from issuance of common stock		$ 14,300	$ 14,300
Common stock, shares issued					820,561
Net proceeds from issuance of common stock					$ 6,900
Sale of common stock		2,214,301	2,214,301
Sales Agreement | JonesTrading
Equity Financing And Warrants [Line Items]
Common stock, par value								$ 0.001
Aggregate offering price of common stock authorized							$ 32,400	$ 7,300
2020 Sales Agreement
Equity Financing And Warrants [Line Items]
Net proceeds from issuance of common stock			$ 27,800
Aggregate offering price of common stock authorized			$ 25,300			$ 54,000
Sale of common stock			4,803,753
Direct Offering
Equity Financing And Warrants [Line Items]
Common stock issued	348,000		348,000
Purchase price per share	$ 9.00		$ 9.00
Pre-funded warrants to purchase shares of common stock	325,500		325,500
Purchase price per warrant	$ 8.999		$ 8.999
Pre-funded warrants outstanding	0		0
Net proceeds from issuance of common stock	$ 5,300		$ 5,300
Percentage of selling commission per additional shares sold	8.00%		8.00%

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