Summary of Business and Significant Accounting Policies - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) Customer Segment $ / shares shares	Dec. 31, 2014 USD ($) Customer $ / shares shares	Dec. 31, 2013 USD ($) Customer shares
Summary Of Significant Accounting Policies [Line Items]
Common stock, par value | $ / shares		$ 0.000004	$ 0.000004
Proceeds from initial public offering	$ 93,093,000	$ 93,093,000
Underwriting discounts and commissions	7,007,000
Paid and unpaid offering expenses	$ 4,024,000
Restricted cash		0	$ 772,000	$ 2,533,000
Unpaid offering costs			219,000
Advertising expenses		$ 598,000	$ 588,000	$ 508,000
Stock-based compensation awards requisite service periods		4 years
Number of shares issued in RSAs | shares		0	0	0
Number of operating segment | Segment		1
Other non-current assets
Summary Of Significant Accounting Policies [Line Items]
Unpaid offering costs		$ 0	$ 863,000
Technology
Summary Of Significant Accounting Policies [Line Items]
Economic lives of finite lived intangible assets		3 years
Impairment charges related to acquired technology		$ 0	$ 426,000	$ 0
Maximum
Summary Of Significant Accounting Policies [Line Items]
Economic lives of finite lived intangible assets		3 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Economic lives of finite lived intangible assets		2 years
Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Number of Customers | Customer		1	0
Revenue
Summary Of Significant Accounting Policies [Line Items]
Number of Customers | Customer		0	0	0
Customer Concentration Risk | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage		18.00%
Customer Concentration Risk | Accounts Receivable | Maximum
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage			10.00%
Customer Concentration Risk | Revenue | Maximum
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage		10.00%	10.00%	10.00%
Common Class A
Summary Of Significant Accounting Policies [Line Items]
Common stock, par value | $ / shares	$ 0.000004	$ 0.000004	$ 0.000004
Common Class A | IPO
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock upon initial public offering, net of offering costs (in shares) | shares	7,150,000
Stock issued, public offering price | $ / shares	$ 14.00
Common Class B
Summary Of Significant Accounting Policies [Line Items]
Common stock, par value | $ / shares	$ 0.000004	$ 0.000004	$ 0.000004
Conversion of redeemable convertible preferred stock to common stock in connection with initial public offering (in shares) | shares	20,673,680	20,673,680
Reclassifications of common stock outstanding | shares	11,305,355
Common Class B | IPO
Summary Of Significant Accounting Policies [Line Items]
Reclassifications of common stock outstanding | shares		11,305,355