Summary of Series B Preferred Stock and Accretion of Dividends (Detail) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Stockholders Equity [Line Items]
Cumulative dividends on Series B preferred stock	$ 1,042	$ 833
Series B Preferred Stock
Stockholders Equity [Line Items]
Balance at December 31, 2018	20,833
Cumulative dividends on Series B preferred stock	1,042
Balance at December 31, 2019	$ 21,875	$ 20,833
Balance at December 31, 2018, Shares	5,208
Cumulative dividends on Series B Preferred stock, Shares	261
Balance at December 31, 2019, Shares	5,469	5,208
Series B Preferred Stock | Tranche One
Stockholders Equity [Line Items]
Balance at December 31, 2018	$ 12,600
Cumulative dividends on Series B preferred stock	630
Balance at December 31, 2019	$ 13,230	$ 12,600
Balance at December 31, 2018, Shares	3,150
Cumulative dividends on Series B Preferred stock, Shares	158
Balance at December 31, 2019, Shares	3,308	3,150
Series B Preferred Stock | Tranche Two
Stockholders Equity [Line Items]
Balance at December 31, 2018	$ 8,233
Cumulative dividends on Series B preferred stock	412
Balance at December 31, 2019	$ 8,645	$ 8,233
Balance at December 31, 2018, Shares	2,058
Cumulative dividends on Series B Preferred stock, Shares	103
Balance at December 31, 2019, Shares	2,161	2,058