Equity Financings and Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
	Jun. 03, 2020	Mar. 31, 2021	Dec. 31, 2020	Apr. 30, 2021	Jul. 22, 2020	Jul. 14, 2020	Jan. 11, 2017
Equity Financing And Warrants [Line Items]
Net proceeds from issuance of common stock		$ 24,070
Common stock, par value		$ 0.001	$ 0.001
Common stock, shares issued		14,410,143	9,548,150
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]
Common stock, shares issued			2,214,301
Net proceeds from issuance of common stock			$ 14,400
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		$ 23,300	$ 28,900
Aggregate offering price of common stock authorized					$ 54,000
Sale of common stock		4,861,993	5,066,279
2020 Sales Agreement | Subsequent Event
Equity Financing And Warrants [Line Items]
Aggregate offering price of common stock authorized				$ 50,000
Direct Offering
Equity Financing And Warrants [Line Items]
Common stock issued	348,000
Purchase price per share	$ 9.00
Pre-funded warrants to purchase shares of common stock	325,500
Purchase price per warrant	$ 8.999
Net proceeds from issuance of common stock	$ 5,300
Percentage of selling commission per additional shares sold	8.00%