Stockholders' Equity - Additional Information (Details)	1 Months Ended					3 Months Ended	12 Months Ended
	Apr. 30, 2020 USD ($) $ / shares shares	Feb. 28, 2019 USD ($) $ / shares shares	Oct. 31, 2018 USD ($) shares	Apr. 30, 2018 USD ($) $ / shares shares	May 31, 2017 USD ($)	Dec. 31, 2020 USD ($) Vote $ / shares shares	Dec. 31, 2020 USD ($) Vote $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) shares
Class Of Stock [Line Items]
Proceeds from issuance of common stock in public offering, net									$ 54,048,000
Underwriting discounts and commissions	$ 8,200,000	$ 4,100,000
Offering costs	800,000	400,000
Shares authorized | shares						510,000,000	510,000,000
Common stock, shares authorized | shares						500,000,000	500,000,000	500,000,000
Preferred stock, shares authorized | shares						10,000,000	10,000,000	10,000,000
Common stock, par value | $ / shares						$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, par value | $ / shares						$ 0.0001	$ 0.0001	$ 0.0001
Number of common stock holders voting right | Vote						1	1
Common stock voting rights							Each holder of common stock is entitled to one vote for each share of common stock held
Common stock dividends declared							$ 0	$ 0
Preferred stock, shares outstanding | shares						0	0	0
Net proceeds from sale of common stock	$ 129,000,000.0	$ 64,500,000
Reduction in exercise price of each warrant from public offering price for pre-funded warrants per share | $ / shares	$ 0.0001	$ 0.0001
Maximum ownership percentage for outstanding warrants to purchase shares of common stock to be exercised	4.99%	4.99%
Period after notice received by company maximum ownership percentage to be effective description							The revised Maximum Ownership Percentage would be effective 61 days after the notice is received by the Company.
Maximum
Class Of Stock [Line Items]
Maximum ownership percentage for outstanding warrants to purchase shares of common stock to be exercised	19.99%
Common Stock
Class Of Stock [Line Items]
Number of shares issued | shares				5,046,510					6,893,000
Public offering price | $ / shares				$ 8.00
Underwriting discounts and commissions				$ 2,400,000
Offering costs				300,000
Follow-on Public Offering | Common Stock
Class Of Stock [Line Items]
Number of shares issued | shares	15,442,303	4,625,000
Public offering price | $ / shares	$ 4.75	$ 8.00
Proceeds from issuance of common stock in public offering, net				$ 37,700,000
Public offering price of warrant | $ / shares	$ 4.7499	$ 7.9999
Follow-on Public Offering | Common Stock | Maximum
Class Of Stock [Line Items]
Warrants to purchase shares | shares	13,610,328	4,000,000
At-the-Market (ATM) Sales Agreement | JonesTrading Institutional Services LLC
Class Of Stock [Line Items]
Number of shares issued | shares			1,845,820			3,245,077
Aggregate offering price of common stock	$ 60,000,000.0				$ 20,000,000.0
Net proceeds from sale of common stock			$ 16,400,000			$ 24,600,000
Proceeds from issuance of common stock gross			$ 17,000,000.0			$ 25,300,000
ATM aggregate amount remaining							$ 34,700,000
Underwriters' Over-allotment Option
Class Of Stock [Line Items]
Number of shares issued | shares	3,789,473	1,125,000
Underwriters' Over-allotment Option | Common Stock
Class Of Stock [Line Items]
Number of shares issued | shares				546,510