Stock-Based Compensation (Details) (USD $)	3 Months Ended						0 Months Ended	3 Months Ended						3 Months Ended								1 Months Ended		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Stock options	Mar. 31, 2013 Stock options	Mar. 31, 2014 Restricted Common Stock Awards	Mar. 31, 2013 Restricted Common Stock Awards	May 06, 2011 Restricted Common Stock Awards Condaptive	Mar. 31, 2014 Restricted Common Stock Awards Condaptive	Mar. 31, 2014 RSUs	Mar. 31, 2013 RSUs	Mar. 31, 2014 Jumptap, Inc. 2005 Stock Option Plan	Dec. 31, 2013 Jumptap, Inc. 2005 Stock Option Plan	Mar. 31, 2014 Jumptap, Inc. 2005 Stock Option Plan Stock options	Mar. 31, 2014 Stock Option Plans	Mar. 31, 2013 Stock Option Plans	Mar. 31, 2014 Stock Option Plans Minimum	Mar. 31, 2013 Stock Option Plans Minimum	Mar. 31, 2014 Stock Option Plans Maximum	Mar. 31, 2013 Stock Option Plans Maximum	Mar. 31, 2014 2006 Equity Incentive Plan	Mar. 31, 2014 2006 Equity Incentive Plan Stock options	Mar. 31, 2012 2012 Equity Incentive Plan	Mar. 31, 2014 2012 Equity Incentive Plan	Mar. 31, 2014 2012 Equity Incentive Plan RSUs
Stock-Based Compensation
Increase in number of shares of common stock reserved for issuance																						10,298,917
Options outstanding to purchase shares of common stock at the end of the period (in shares)												861,311	453,717	8,121,589							2,436,049		5,231,823
RSUs outstanding at the end of the period (in shares)																								1,935,026
Number of shares under contingent right to receive share of common stock																								1
Shares available for future grants											0									0			2,766,176
Total recognized stock-based compensation expense	$ 3,772,000	$ 1,657,000	$ 1,596,000	$ 490,000	$ 65,000	$ 803,000			$ 2,111,000	$ 364,000
Stock-based compensation expense related to acceleration and modification of equity awards	531,000
Assumptions used for estimating the fair value of stock options granted to employees
Risk-free interest rate (as a percent)																1.80%	1.00%	2.00%	1.10%
Expected life															6 years	6 years		6 years 3 months 18 days
Expected volatility (as a percent)															55.00%	53.00%		54.00%
Dividend yield (as a percent)														0.00%	0.00%
Weighted-average grant date fair value (in dollars per share)														$ 3.59	$ 4.74
Number
Options outstanding at the beginning of the period (in shares)												861,311	453,717	7,665,097							2,436,049		5,231,823
Granted (in shares)														2,232,935
Exercised (in shares)														(385,313)
Forfeited (in shares)														(1,391,130)
Options outstanding at the end of the period (in shares)												861,311	453,717	8,121,589							2,436,049		5,231,823
Options exercisable at the end of the period (in shares)														3,046,974
Options vested and expected to vest at the end of the period (in shares)														7,869,720
Weighted-Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share)														$ 5.28
Granted (in dollars per share)														$ 6.81
Exercised (in dollars per share)														$ 2.69
Forfeited (in dollars per share)														$ 6.56
Options outstanding at the end of the period (in dollars per share)														$ 5.60
Options exercisable at the end of the period (in dollars per share)														$ 3.30
Options vested and expected to vest at the end of the period (in dollars per share)														$ 5.61
Weighted-Average Remaining Contractual Term
Options outstanding at the end of the period														8 years 3 months 11 days
Options exercisable at the end of the period														5 years 10 months 28 days
Options vested and expected to vest at the end of the period														8 years
Aggregate Intrinsic Value
Options outstanding at the end of the period														14,417,000
Options exercisable at the end of the period														12,133,000
Options vested and expected to vest at the end of the period														13,970,000
Stock-based compensation, additional disclosures
Compensation cost related to unvested awards not yet recognized														17,400,000
Weighted-average period over which unrecognized compensation expense is expected to be recognized														3 years 3 months 18 days										2 years 6 months
Aggregate intrinsic value of stock options exercised														1,700,000	2,000,000
Total fair value of stock options which vested														1,600,000	606,000
Restricted Common Stock Awards
Number of shares issued to certain stockholders of acquiree entity who became employees of the Company							1,448,080																	965,212
Period of anniversary of issuance on which portion of the shares were released							1 year
Repurchase price of unvested shares (in dollars per share)								$ 0.001
Number of shares on which restrictions were released								1,384,412
Shares remaining under restriction								63,668
Unrecognized compensation expense relating to the restricted stock awards and restricted stock units					178,000																			12,900,000
Aggregate intrinsic value of the unvested restricted stock					$ 441,000
Number
RSUs outstanding at the beginning of the period (in shares)																								1,177,288
Granted (in shares)							1,448,080																	965,212
Vested (in shares)																								(207,474)
RSUs outstanding at the end of the period (in shares)																								1,935,026
Weighted Average Grant Date Fair Value (in dollars per share)
RSUs outstanding at the beginning of the period (in dollars per share)																								$ 7.80
Granted (in dollars per share)																								$ 6.92
Vested (in dollars per share)																								$ 7.57
RSUs outstanding at the end of the period (in dollars per share)																								$ 7.39