Stockholders' Equity - Additional Information (Detail) - USD ($)				3 Months Ended
	Jan. 24, 2020	Nov. 01, 2019	Jul. 07, 2017	Mar. 31, 2020	May 06, 2020	Dec. 31, 2019	Jan. 17, 2017
Shareholders Equity [Line Items]
Aggregate number of common stock shares issued				7,259,000		3,466,000
Net proceeds from sale of common stock	$ 15,900,000
Fair value allocated less issuance costs				$ 15,931,000
Common Shares [Member]
Shareholders Equity [Line Items]
Common stock, shares issued				3,650,000
Fair value allocated less issuance costs				$ 4,000
Sales Agreement [Member]
Shareholders Equity [Line Items]
Percentage of commission on gross proceeds per share sold			3.00%
Aggregate number of common stock shares issued				305,522
Common stock, shares issued				0
Average selling price per share				$ 129.80
Gross proceeds from sale of common stock				$ 39,600,000
Net proceeds from sale of common stock				$ 38,200,000
Sales Agreement [Member] | Subsequent Event [Member]
Shareholders Equity [Line Items]
Aggregate offering price					$ 40,400,000
Sales Agreement [Member] | Maximum [Member]
Shareholders Equity [Line Items]
Aggregate offering price			$ 80,000,000				$ 40,000,000
Armistice Capital, LLC [Member]
Shareholders Equity [Line Items]
Net proceeds from common stock offering		$ 7,100,000
Armistice Capital, LLC [Member] | Common Shares [Member]
Shareholders Equity [Line Items]
Common stock, shares issued		300,000
Fair value allocated less issuance costs		$ 600,000
Armistice Capital, LLC [Member] | Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock		300,000
Fair value allocated less issuance costs		$ 2,900,000
Armistice Capital, LLC [Member] | Pre-funded Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock		1,830,493
Warrant exercise price		$ 0.01
Fair value allocated less issuance costs		$ 3,600,000
Warrants exercised		400,000
Armistice Capital, LLC [Member] | Pre-funded Accompanying Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock		1,830,493
Armistice Capital, LLC [Member] | Common Stock And Accompanying Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Share price		$ 3.755
Armistice Capital, LLC [Member] | Pre-funded Warrant And Accompanying Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Share price		3.745
Armistice Capital, LLC [Member] | Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Warrant exercise price		$ 3.62
Warrant expiration period		5 years
Private Placement with Armistice Capital, LLC [Member]
Shareholders Equity [Line Items]
Gross proceeds from sale of common stock	$ 10,000,000
Private Placement with Armistice Capital, LLC [Member] | Common Shares [Member]
Shareholders Equity [Line Items]
Common stock, shares issued	1,270,000
Private Placement with Armistice Capital, LLC [Member] | Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	1,270,000
Private Placement with Armistice Capital, LLC [Member] | Pre-funded Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	2,063,334
Warrant exercise price	$ 0.001
Private Placement with Armistice Capital, LLC [Member] | Pre-funded Accompanying Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	2,063,334
Private Placement with Armistice Capital, LLC [Member] | Common Stock And Accompanying Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Share price	$ 3.00
Private Placement with Armistice Capital, LLC [Member] | Pre-funded Warrant And Accompanying Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Share price	2.999
Private Placement with Armistice Capital, LLC [Member] | Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Warrant exercise price	$ 2.87
Warrant expiration period	5 years
Healthcare-Focused Institutional Investor [Member]
Shareholders Equity [Line Items]
Gross proceeds from sale of common stock	$ 7,500,000
Healthcare-Focused Institutional Investor [Member] | Common Shares [Member]
Shareholders Equity [Line Items]
Common stock, shares issued	2,380,105
Healthcare-Focused Institutional Investor [Member] | Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	2,380,105
Healthcare-Focused Institutional Investor [Member] | Pre-funded Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	120,000
Warrant exercise price	$ 0.001
Healthcare-Focused Institutional Investor [Member] | Pre-funded Accompanying Warrants [Member]
Shareholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	120,000
Healthcare-Focused Institutional Investor [Member] | Common Stock And Accompanying Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Share price	$ 3.00
Healthcare-Focused Institutional Investor [Member] | Pre-funded Warrant And Accompanying Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Share price	2.999
Healthcare-Focused Institutional Investor [Member] | Common Stock Warrant [Member]
Shareholders Equity [Line Items]
Warrant exercise price	$ 2.87
Warrant expiration period	5 years