Stockholders' Equity - Schedule of Warrants to Purchase Shares of Company's Common Stock (Detail) shares in Thousands	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	218
February 2015 [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	10
Warrants, Exercise Price Per Share | $ / shares	$ 13.32
Warrants Expiration Date	2020-02
March 2016 [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	208
Warrants, Exercise Price Per Share | $ / shares	$ 3.25
Warrants Expiration Date	2021-03