Original and Further Restatement of the Consolidated Financial Statements - Effects of Further Adjustments to Previously Filed Consolidated Income Statements (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
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 (loss) income	6,704	6,920	6,675	12,988
Other income and (expense)	(129)	(1,662)	(869)	2,560
Income (loss) before income taxes	6,575	5,258	5,806	15,548
Income tax expense	(3,309)	(3,246)	(4,488)	(7,610)
Net income (loss) from continuing operations	3,266	2,012	1,318	7,938
Co-Pay and Self-Pay Revenue [Member]
Net sales		(336)		(1,789)
Cost of sales
Gross profit		(336)		(1,789)
Operating expenses
Sales and marketing		(336)		(1,789)
General and administrative
Research and development
Amortization of intangible assets
Total operating expenses		(336)		(1,789)
Operating (loss) income
Other income and (expense)
Income (loss) before income taxes
Income tax expense
Net income (loss) from continuing operations
Bad Debt Timing [Member]
Net sales
Cost of sales
Gross profit
Operating expenses
Sales and marketing				1,455
General and administrative
Research and development
Amortization of intangible assets
Total operating expenses				1,455
Operating (loss) income				(1,455)
Other income and (expense)
Income (loss) before income taxes				(1,455)
Income tax expense				509
Net income (loss) from continuing operations				(946)
Accounts Receivable Reserve [Member]
Net sales		(313)		123
Gross profit		(313)		123
Operating expenses
Sales and marketing		48		40
Total operating expenses		48		40
Operating (loss) income		(361)		83
Income (loss) before income taxes		(361)		83
Income tax expense		126		(29)
Net income (loss) from continuing operations		(235)		54
Intercompany Profit [Member]
Cost of sales		363		242
Gross profit		(363)		(242)
Operating expenses
Operating (loss) income		(363)		(242)
Income (loss) before income taxes		(363)		(242)
Income tax expense		127		85
Net income (loss) from continuing operations		(236)		(157)
Inventory [Member]
Cost of sales		1,259		2,079
Gross profit		(1,259)		(2,079)
Operating expenses
Operating (loss) income		(1,259)		(2,079)
Income (loss) before income taxes		(1,259)		(2,079)
Income tax expense		441		728
Net income (loss) from continuing operations		(818)		(1,351)
Other Adjustments [Member]
Net sales		9		(68)
Cost of sales		16		(459)
Gross profit		(7)		391
Operating expenses
Sales and marketing		(83)		713
General and administrative		(23)		(112)
Total operating expenses		(106)		601
Operating (loss) income		99		(210)
Other income and (expense)		15		33
Income (loss) before income taxes		114		(177)
Income tax expense		(943)		(1,225)
Net income (loss) from continuing operations		(829)		(1,402)
Previously Reported [Member]
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 (loss) income		8,804		16,891
Other income and (expense)		(1,677)		2,527
Income (loss) before income taxes		7,127		19,418
Income tax expense		(2,997)		(7,678)
Net income (loss) from continuing operations		4,130		11,740
Restatement Adjustments [Member]
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 (loss) income		(1,884)		(3,903)
Other income and (expense)		15		33
Income (loss) before income taxes		(1,869)		(3,870)
Income tax expense		(249)		68
Net income (loss) from continuing operations		(2,118)		(3,802)
Restatement Adjustments [Member] | Bad Debt Timing [Member]
Operating expenses
Sales and marketing		$ 0		$ 1,500