Earnings (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ (6,364)	$ (5,968)	$ (9,202)	$ 1,533	$ (6,904)	$ (5,977)	$ (6,930)	$ (5,178)	$ (20,001)	$ (24,989)
Weighted average common shares outstanding used to compute basic EPS									37,994	37,582
Dilutive effect of stock based awards									0	0
Weighted average common shares outstanding used to compute diluted EPS									37,994	37,582
Net income (loss) per share - basic	$ (0.17)	$ (0.16)	$ (0.24)	$ 0.04	$ (0.18)	$ (0.16)	$ (0.18)	$ (0.14)	$ (0.53)	$ (0.66)
Net income (loss) per share - diluted	$ (0.17)	$ (0.16)	$ (0.24)	$ 0.04	$ (0.18)	$ (0.16)	$ (0.18)	$ (0.14)	$ (0.53)	$ (0.66)
Shares of common stock excluded from the calculation of diluted net income per share because of antidilutive effect									7,700	6,500