Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended		6 Months Ended
	Apr. 02, 2019 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Jul. 31, 2019 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	Mar. 31, 2020 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares
Class of Stock [Line Items]
Discounts, commissions and offering expenses				$ 1,186	$ 28
Aggregate offering price of common stock shares issued				$ 11,915
Grant date fair value of the common warrants, per share | $ / shares		$ 1.78		$ 1.78		$ 1.78
Grant date fair value of the common warrants						$ 23,025
Risk Free Rate [Member]
Class of Stock [Line Items]
Warrants and rights, measurement input		2.23		2.23		2.23
Expected Term [Member]
Class of Stock [Line Items]
Warrants and rights outstanding, term		5 years		5 years		5 years
Volatility [Member]
Class of Stock [Line Items]
Warrants and rights, measurement input		76		76		76
Common Stock [Member]
Class of Stock [Line Items]
Stock issued during period, shares | shares				11,425,118
Aggregate offering price of common stock shares issued				$ 11
Sales Agreement [Member] | JonesTrading [Member]
Class of Stock [Line Items]
Discounts, commissions and offering expenses						$ 24
Aggregate number of common stock shares issued and sold | shares						1,263,059
Gross proceeds from common stock shares issued and sold						$ 762
Sales Agreement [Member] | JonesTrading [Member] | Maximum [Member]
Class of Stock [Line Items]
Aggregate offering price of common stock shares issued			$ 13,265
Underwritten Public Offering [Member]
Class of Stock [Line Items]
Stock issued during period, shares | shares		10,162,059
Additional shares of common stock issued upon partial exercise of option | shares		1,071,149
Shares issued, price per share | $ / shares		$ 1.10		$ 1.10		$ 1.10
Gross proceeds from issuance of common stock		$ 11,178
Discounts, commissions and offering expenses		$ 932
Private Placement [Member]
Class of Stock [Line Items]
Discounts, commissions and offering expenses	$ 2,175
Aggregate gross proceeds from private placement	$ 26,000
Private Placement [Member] | Stock Units [Member] | Purchase Agreement One [Member]
Class of Stock [Line Items]
Shares issued, price per share | $ / shares	$ 2.01
Aggregate number of common stock shares issued and sold | shares	11,838,582
Private Placement [Member] | Stock Units [Member] | Purchase Agreement Two [Member]
Class of Stock [Line Items]
Shares issued, price per share | $ / shares	$ 2.01
Aggregate number of common stock shares issued and sold | shares	1,096,741
Private Placement [Member] | Common Warrants [Member] | Purchase Agreement One [Member]
Class of Stock [Line Items]
Aggregate shares purchase for warrants | shares	11,838,582
Warrants exercisable, exercise price | $ / shares	$ 2.00
Warrants and rights outstanding, term	5 years
Private Placement [Member] | Common Stock [Member] | Purchase Agreement One [Member]
Class of Stock [Line Items]
Stock repurchase program, number of shares to be purchased | shares	11,838,582
Private Placement [Member] | Common Stock [Member] | Purchase Agreement Two [Member]
Class of Stock [Line Items]
Stock repurchase program, number of shares to be purchased | shares	1,096,741
Private Placement [Member] | Pre-funded Warrants [Member] | Purchase Agreement Two [Member]
Class of Stock [Line Items]
Aggregate shares purchase for warrants | shares	1,096,741
Warrants exercisable, exercise price | $ / shares	$ 0.01