Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018		Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017
Net revenue:
Revenue	$ 42,553,000		$ 36,389,000	$ 76,678,000		$ 65,688,000
Cost of revenue:
Cost of revenue	20,176,000		15,343,000	36,967,000		29,121,000
Gross profit	22,377,000		21,046,000	39,711,000		36,567,000
Operating expenses:
Sales and marketing	15,535,000		12,787,000	28,623,000		23,560,000
Research and development	4,095,000		2,981,000	7,651,000		5,926,000
General and administrative	4,902,000		3,548,000	10,341,000		6,764,000
Total operating expenses	24,532,000		19,316,000	46,615,000		36,250,000
Income (loss) from operations	(2,155,000)		1,730,000	(6,904,000)		317,000
Interest and other income (expense), net	(129,000)	[1]	276,000	(31,000)	[1]	549,000
Income (loss) before income taxes	(2,284,000)		2,006,000	(6,935,000)		866,000
Provision (benefit) for income taxes	(712,000)		59,000	(3,331,000)		(59,000)
Net income (loss)	$ (1,572,000)		$ 1,947,000	$ (3,604,000)		$ 925,000
Net income (loss) per share:
Basic (in dollars per share)	$ (0.11)		$ 0.14	$ (0.26)		$ 0.07
Diluted (in dollars per share)	$ (0.11)		$ 0.13	$ (0.26)		$ 0.06
Weighted-average number of shares used in per share calculations:
Basic (in shares)	13,709		13,935	13,649		13,888
Diluted (in shares)	13,709		14,629	13,649		14,633
Product [Member]
Net revenue:
Revenue	$ 37,650,000		$ 31,727,000	$ 66,914,000		$ 56,202,000
Cost of revenue:
Cost of revenue	17,045,000		13,840,000	30,967,000		24,984,000
Operating expenses:
Sales and marketing	15,535,000			28,623,000
Service [Member]
Net revenue:
Revenue	4,903,000		4,662,000	9,764,000		9,486,000
Cost of revenue:
Cost of revenue	$ 3,131,000		$ 1,503,000	$ 6,000,000		$ 4,137,000

[1] Included in interest and other income, net is the estimated interest expense for advance payment related to contract services under the new revenue standard going forward. Adoption of the standard had no impact to total net cash from or used in operating, investing, or financing activities within the Condensed Consolidated Statements of Cash Flows.