Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2014

Significant Accounting Policies

Summary of financial assets and liabilities measured at fair value on a recurring basis

	At December 31, 2012								At December 31, 2013								At June 30, 2014 (unaudited)
	Level 1		Level 2		Level 3		Total Fair Value		Level 1		Level 2		Level 3		Total Fair Value		Level 1		Level 2		Level 3		Total Fair Value
Cash equivalents	$	6,807	$	—	$	—	$	6,807	$	7,726	$	—	$	—	$	7,726	$	98,929	$	—	$	—	$	98,929
Total Assets	$	6,807	$	—	$	—	$	6,807	$	7,726	$	—	$	—	$	7,726	$	98,929	$	—	$	—	$	98,929
Contingent consideration	$	—	$	—	$	1,798	$	1,798	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Total Liabilities	$	—	$	—	$	1,798	$	1,798	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—

Summary of changes in Level 3 financial instruments

	Warrants			Contingent Consideration
Fair value, at December 31, 2010	$	670		$	—
Contingent consideration from acquisitions		—			428
Changes in fair value		1,882			—
Conversion of preferred stock warrants to common stock warrants		(2,552	)		—
Fair value, at December 31, 2011	$	—		$	428
Changes in fair value		—			1,370
Fair value, at December 31, 2012	$	—		$	1,798
Changes in fair value		—			95
Payments on contingent consideration		—			(1,893	)
Fair value, at December 31, 2013 and June 30, 2014 (unaudited)	$	—		$	—

Summary of changes in the allowance for doubtful accounts and sales allowances

	Year Ended December 31,
	2011			2012			2013
Allowances, at beginning of period	$	433		$	2,369		$	1,621
Charged as a reduction of revenue		6,304			6,898			6,985
Charged to bad debt expense in general and administrative expenses		137			668			153
Write-offs, net of recoveries		(4,505	)		(8,314	)		(6,575	)
Allowances, at end of period	$	2,369		$	1,621		$	2,184

Schedule of fair value of awards granted to employees using the Black Scholes option pricing model

	Year Ended December 31,									Six Months Ended June 30,
	2011			2012			2013			2013			2014
										(unaudited)
Risk-free interest rate		2.04	%		0.96	%		1.41	%		1.10	%		1.95	%
Expected term (years)		6.01			6.00			6.06			6.07			6.26
Expected volatility		48	%		60	%		61	%		63	%		58	%
Dividend yield		—			—			—			—			—

Schedule of anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders

	December 31,						June 30,
	2011		2012		2013		2013		2014
							(unaudited)
Options to purchase common stock		15,243		15,419		18,363		16,078		26,665
Common stock warrants		8,697		5,154		5,931		5,251		3,981
Conversion of convertible preferred stock		—		—		2,857		2,857		—
Unvested restricted stock awards		469		122		55		95		741
Contingently redeemable shares		—		126		—		189		—
Convertible promissory notes		—		3,444		—		—		—
Total shares excluded from net loss per share attributable to common stockholders		24,409		24,265		27,206		24,470		31,387

Internally developed software

Significant Accounting Policies

Schedule of amortization expense with respect to capitalized software development costs

Years ended December 31,
2014		4,626
2015		3,521
2016		1,690
Total amortization expense	$	9,837

Preferred Stock Warrants converted to common stock warrants

Significant Accounting Policies

Schedule of fair value of convertible preferred stock warrants using the Black-Scholes option pricing model

	2011
Risk-free interest rate	0.01% - 0.30%
Expected term (years)	0.3 - 2.7
Expected volatility	45.00%
Dividend yield	—