Organization and Summary of Significant Accounting Policies - Net Sales by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Net sales by geographic area	$ 90,262	$ 71,882	$ 249,147	$ 186,168
Percentage of net sales by geographic area	100.00%	100.00%	100.00%	100.00%
United States
Segment Reporting Information [Line Items]
Net sales by geographic area	$ 73,203	$ 60,558	$ 204,155	$ 155,245
Percentage of net sales by geographic area	81.10%	84.20%	81.90%	83.40%
Other Countries
Segment Reporting Information [Line Items]
Net sales by geographic area	$ 17,059	$ 11,324	$ 44,992	$ 30,923
Percentage of net sales by geographic area	18.90%	15.80%	18.10%	16.60%
UNITED KINGDOM
Segment Reporting Information [Line Items]
Percentage of net sales by geographic area	10.50%