Stockholders' Equity (Detail) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended
	Mar. 23, 2020 USD ($) $ / shares shares	Feb. 11, 2020 USD ($) $ / shares shares	Mar. 31, 2018 shares	Mar. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($)	May 23, 2019 $ / shares shares
Class of Stock [Line Items]
Number of shares for purchase under warrant (in shares)	9,000,000.0					1,500,000
Common stock purchase price (in dollars per share) | $ / shares	$ 1.00					$ 10.00
Warrant term (in years)				5 years
Fair value of warrant | $	$ 3,600
Warrant liability | $				$ 2,384	$ 0
Conversion ratio				1
Term loan | Amended 2019 Term Loan
Class of Stock [Line Items]
Increase of warrant fair value | $	$ 300
At-the-Market Program
Class of Stock [Line Items]
Net proceeds from sale of stock | $				$ 100
Number of common stock issued (in shares)				142,119
Sale of stock, remaining availability for sale amount | $				$ 389,200
Common Stock
Class of Stock [Line Items]
Number of shares sold in transaction (in shares)		2,114,591
Sale of stock, price per share (in dollars per share) | $ / shares		$ 6.36
Net proceeds from sale of stock | $		$ 13,100
Convertible Preferred Stock
Class of Stock [Line Items]
Number of shares sold in transaction (in shares)			6,100,000
Immediately
Class of Stock [Line Items]
Number of shares for purchase under warrant (in shares)	3,000,000
September 23, 2020
Class of Stock [Line Items]
Number of shares for purchase under warrant (in shares)	2,000,000
March 23, 2021
Class of Stock [Line Items]
Number of shares for purchase under warrant (in shares)	2,000,000
June 23, 2021
Class of Stock [Line Items]
Number of shares for purchase under warrant (in shares)	2,000,000