Original and Further Restatement of the Consolidated Financial Statements - Effects of Further Restatements of Consolidated Statement of Operations and Comprehensive Income (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Product sales	$ 88,579	$ 85,929	$ 176,879	$ 176,170
Marketing service fees	12,406	11,711	24,120	23,749
Net sales	100,985	97,640	200,999	199,919
Cost of sales	25,414	21,884	52,187	47,725
Gross profit	75,571	75,756	148,812	152,194
Operating expenses
Sales and marketing	42,013	44,539	83,184	90,383
General and administrative	17,553	15,181	34,829	33,422
Research and development	6,313	8,551	12,246	14,292
Amortization of intangible assets	661	565	1,245	1,109
Total operating expenses	68,867	68,836	142,137	139,206
Operating income	6,704	6,920	6,675	12,988
Other income and expense
Interest expense, net	(492)	(455)	(960)	(997)
Other expense	363	(1,207)	91	3,557
Total other income (expense)	(129)	(1,662)	(869)	2,560
Income before income taxes	6,575	5,258	5,806	15,548
Income tax expense	(3,309)	(3,246)	(4,488)	(7,610)
Net income from continuing operations	3,266	2,012	1,318	7,938
Discontinued operations (Note 15)
Loss from discontinued operations	(5,829)	(8,092)	(6,623)	(12,052)
Income tax benefit	1,880	3,069	2,114	4,550
Net loss from discontinued operations	(3,949)	(5,023)	(4,509)	(7,502)
Net income (loss)	(683)	(3,011)	(3,191)	436
Net income (loss) per common share- basic:
Net income from continuing operations	$ 0.18	$ 0.11	$ (0.07)	$ 0.41
Net loss from discontinued operations	$ (0.22)	$ (0.27)	$ (0.24)	$ (0.39)
Net income (loss) per common share- basic	$ (0.04)	$ (0.16)	$ (0.17)	$ 0.02
Net income (loss) per common share- diluted:
Net income from continuing operations	$ 0.18	$ 0.10	$ (0.07)	$ 0.41
Net loss from discontinued operations	$ (0.22)	$ (0.26)	$ (0.24)	$ (0.39)
Net income (loss) per common share- diluted	$ (0.04)	$ (0.16)	$ (0.17)	$ 0.02
Weighted average number of common shares:
Basic	18,445,348	19,140,520	18,322,185	19,285,004
Diluted	18,621,192	19,270,044	18,435,128	19,483,715
Comprehensive loss	(516)	(3,500)	(2,545)	(3,050)
Previously Reported [Member]
Product sales		86,633		177,969
Marketing service fees		11,647		23,684
Net sales		98,280		201,653
Cost of sales		20,246		45,863
Gross profit		78,034		155,790
Operating expenses
Sales and marketing		44,910		89,964
General and administrative		15,204		33,534
Research and development		8,551		14,292
Amortization of intangible assets		565		1,109
Total operating expenses		69,230		138,899
Operating income		8,804		16,891
Other income and expense
Interest expense, net		(470)		(1,030)
Other expense		(1,207)		3,557
Total other income (expense)		(1,677)		2,527
Income before income taxes		7,127		19,418
Income tax expense		(2,997)		(7,678)
Net income from continuing operations		4,130		11,740
Discontinued operations (Note 15)
Loss from discontinued operations		(9,154)		(13,588)
Income tax benefit		2,707		4,031
Net loss from discontinued operations		(6,447)		(9,557)
Net income (loss)		(2,317)		2,183
Net income (loss) per common share- basic:
Net income from continuing operations		$ 0.22		$ 0.61
Net loss from discontinued operations		$ (0.34)		$ (0.50)
Net income (loss) per common share- basic		$ (0.12)		$ 0.11
Net income (loss) per common share- diluted:
Net income from continuing operations		$ 0.21		$ 0.60
Net loss from discontinued operations		$ (0.33)		$ (0.49)
Net income (loss) per common share- diluted		$ (0.12)		$ 0.11
Weighted average number of common shares:
Basic		19,140,520		19,285,004
Diluted		19,270,044		19,483,715
Comprehensive loss		(2,836)		(1,362)
Restatement Adjustments [Member]
Product sales		(704)		(1,799)
Marketing service fees		64		65
Net sales		(640)		(1,734)
Cost of sales		1,638		1,862
Gross profit		(2,278)		(3,596)
Operating expenses
Sales and marketing		(371)		419
General and administrative		(23)		(112)
Research and development
Amortization of intangible assets
Total operating expenses		(394)		307
Operating income		(1,884)		(3,903)
Other income and expense
Interest expense, net		15		33
Other expense
Total other income (expense)		15		33
Income before income taxes		(1,869)		(3,870)
Income tax expense		(249)		68
Net income from continuing operations		(2,118)		(3,802)
Discontinued operations (Note 15)
Loss from discontinued operations		1,062		1,536
Income tax benefit		362		519
Net loss from discontinued operations		1,424		2,055
Net income (loss)		(694)		(1,747)
Net income (loss) per common share- basic:
Net income from continuing operations		$ (0.11)		$ (0.20)
Net loss from discontinued operations		$ 0.07		$ 0.11
Net income (loss) per common share- basic		$ (0.04)		$ (0.09)
Net income (loss) per common share- diluted:
Net income from continuing operations		$ (0.11)		$ (0.19)
Net loss from discontinued operations		$ 0.07		$ 0.10
Net income (loss) per common share- diluted		$ (0.04)		$ (0.09)
Weighted average number of common shares:
Basic
Diluted
Comprehensive loss		$ (664)		$ (1,688)