Share-Based Compensation - Schedule of Information with Respect to Outstanding and Exercisable Stock Options (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Options Outstanding	1,227,074	2,437,609	2,818,433	2,868,053
Options Outstanding, Weighted Average Exercise Price	$ 10.07	$ 9.32	$ 9.59	$ 9.86
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	4 years 10 months 24 days
Options Exercisable, Number Exercisable	1,037,202
Options Exercisable, Weighted Average Exercise Price	$ 9.70
Range of Exercise Prices $2.82 - $3.93 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	2.82
Range of Exercise Prices, Maximum	$ 3.93
Options Outstanding, Number of Options Outstanding	170,656
Options Outstanding, Weighted Average Exercise Price	$ 3.51
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	3 years 7 months 13 days
Options Exercisable, Number Exercisable	170,656
Options Exercisable, Weighted Average Exercise Price	$ 3.51
Range of Exercise Prices $4.07 - $4.49 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	4.07
Range of Exercise Prices, Maximum	$ 4.49
Options Outstanding, Number of Options Outstanding	142,764
Options Outstanding, Weighted Average Exercise Price	$ 4.32
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	5 years 18 days
Options Exercisable, Number Exercisable	142,764
Options Exercisable, Weighted Average Exercise Price	$ 4.32
Range of Exercise Prices $5.00 - $5.96 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	5.00
Range of Exercise Prices, Maximum	$ 5.96
Options Outstanding, Number of Options Outstanding	179,199
Options Outstanding, Weighted Average Exercise Price	$ 5.82
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	4 years 5 months 19 days
Options Exercisable, Number Exercisable	179,199
Options Exercisable, Weighted Average Exercise Price	$ 5.82
Range of Exercise Prices $6.51 - $8.30 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	6.51
Range of Exercise Prices, Maximum	$ 8.30
Options Outstanding, Number of Options Outstanding	198,556
Options Outstanding, Weighted Average Exercise Price	$ 7.65
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	4 years 5 months 26 days
Options Exercisable, Number Exercisable	139,466
Options Exercisable, Weighted Average Exercise Price	$ 7.37
Range of Exercise Prices $9.69 - $13.15 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	9.69
Range of Exercise Prices, Maximum	$ 13.15
Options Outstanding, Number of Options Outstanding	72,794
Options Outstanding, Weighted Average Exercise Price	$ 9.94
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	6 years 5 months 1 day
Options Exercisable, Number Exercisable	72,794
Options Exercisable, Weighted Average Exercise Price	$ 9.94
Range of Exercise Prices $13.80 - $13.80 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	13.80
Range of Exercise Prices, Maximum	$ 13.80
Options Outstanding, Number of Options Outstanding	236,452
Options Outstanding, Weighted Average Exercise Price	$ 13.80
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	7 years 2 months 4 days
Options Exercisable, Number Exercisable	105,670
Options Exercisable, Weighted Average Exercise Price	$ 13.80
Range of Exercise Prices $15.39 - $15.39 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	15.39
Range of Exercise Prices, Maximum	$ 15.39
Options Outstanding, Number of Options Outstanding	56,119
Options Outstanding, Weighted Average Exercise Price	$ 15.39
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	7 years 4 months 28 days
Options Exercisable, Number Exercisable	56,119
Options Exercisable, Weighted Average Exercise Price	$ 15.39
Range of Exercise Prices $21.29 - $21.29 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	21.29
Range of Exercise Prices, Maximum	$ 21.29
Options Outstanding, Number of Options Outstanding	41,958
Options Outstanding, Weighted Average Exercise Price	$ 21.29
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	8 years 7 months 9 days
Options Exercisable, Number Exercisable	41,958
Options Exercisable, Weighted Average Exercise Price	$ 21.29
Range of Exercise Prices $21.80 - $21.80 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	21.80
Range of Exercise Prices, Maximum	$ 21.80
Options Outstanding, Number of Options Outstanding	48,576
Options Outstanding, Weighted Average Exercise Price	$ 21.80
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	2 months 12 days
Options Exercisable, Number Exercisable	48,576
Options Exercisable, Weighted Average Exercise Price	$ 21.80
Range of Exercise Prices $22.13 - $22.13 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	22.13
Range of Exercise Prices, Maximum	$ 22.13
Options Outstanding, Number of Options Outstanding	80,000
Options Outstanding, Weighted Average Exercise Price	$ 22.13
Options Outstanding, Weighted Average Remaining Contractual Term (in Years)	4 months 17 days
Options Exercisable, Number Exercisable	80,000
Options Exercisable, Weighted Average Exercise Price	$ 22.13