Consolidated Statements of Operations Information for Each of Previous Eight Quarters (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information [Line Items]
Revenue	$ 108,648	$ 94,060	$ 87,462	$ 76,090	$ 69,474	$ 69,445	$ 70,692	$ 60,634	$ 366,260	$ 270,245	$ 194,032
Gross profit	60,485	54,434	50,599	44,108	39,353	38,020	39,984	33,789
Operating expenses	91,229	73,099	67,925	64,184	63,580	61,481	59,638	49,463
Net income	$ 19,698	$ 14,552	$ 15,861	$ 9,815	$ 3,604	$ 1,659	$ 8,095	$ 8,053	$ 59,926	$ 21,411	$ 16,617
Earnings per share
Basic	$ 0.37	$ 0.28	$ 0.30	$ 0.19	$ 0.07	$ 0.03	$ 0.17	$ 0.18	$ 1.14	$ 0.44	$ 0.38
Diluted	$ 0.36	$ 0.27	$ 0.30	$ 0.18	$ 0.07	$ 0.03	$ 0.17	$ 0.17	$ 1.11	$ 0.44	$ 0.37