Selected Quarterly Financial Data (unaudited) - Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Total revenues	$ 63,597	$ 40,857	$ 31,488	$ 46,673	$ 50,170	$ 33,539	$ 29,706	$ 61,995	$ 182,615	$ 175,410	$ 155,741
Cost of sales (excludes amortization of intangible assets)	21,263	16,768	15,902	20,247	18,461	15,297	13,671	19,547	74,180	66,976	61,285
Gross profit	40,763	22,518	14,015	24,855	30,126	16,695	14,524	41,010
Total costs and expenses (3)	50,682	50,978	41,473	48,690	49,935	39,334	36,659	44,640	191,823	170,568	146,055
Net income (loss)	$ 7,113	$ (5,767)	$ (6,908)	$ (1,512)	$ 1,139	$ (4,361)	$ (1,755)	$ 12,367	$ (7,074)	$ 7,390	$ 4,993
Basic (loss) earnings per share	$ 0.20	$ (0.17)	$ (0.20)	$ (0.04)	$ 0.03	$ (0.13)	$ (0.05)	$ 0.37	$ (0.21)	$ 0.22	$ 0.15
Diluted net earnings (loss) per share	$ 0.20	$ (0.17)	$ (0.20)	$ (0.04)	$ 0.03	$ (0.13)	$ (0.05)	$ 0.36	$ (0.21)	$ 0.21	$ 0.15