Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015		Dec. 31, 2014
Accounts receivable, net of allowance for doubtful accounts	$ 90		$ 79
Temporary equity, par value	$ 0.000004		$ 0.000004
Temporary equity, shares authorized	0		20,542,012
Temporary equity, shares issued	0	[1]	20,454,489
Temporary equity, shares outstanding	0		20,454,489
Temporary equity, liquidation preference			$ 117,636
Common stock, par value	$ 0.000004		$ 0.000004
Common stock, shares authorized	0		50,000,000
Common stock, shares, issued	0		11,189,360
Common stock, shares, outstanding	0		11,189,360
Common Class A
Common stock, par value	$ 0.000004		$ 0.000004
Common stock, shares authorized	1,000,000,000		0
Common stock, shares, issued	14,931,016		0
Common stock, shares, outstanding	14,931,016		0
Common Class B
Common stock, par value	$ 0.000004		$ 0.000004
Common stock, shares authorized	100,000,000		0
Common stock, shares, issued	24,296,346		0
Common stock, shares, outstanding	24,296,346		0

[1] no