Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended			12 Months Ended
	Aug. 31, 2015	Jul. 31, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Aug. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares outstanding				101,282,000	24,249,000
Common stock reserved for issuance				27,307,000	67,890,000
Unvested exercisable shares				517,285	469,000
Unvested exercisable shares, vesting period				3 years 2 months 12 days
Unvested options exercised				0	0
Unvested options subject to repurchase, outstanding				0	0
Weighted-average grant-date fair value of stock options granted				$ 4.56	$ 3.72	$ 1.77
Total intrinsic value of options exercised				$ 8,100,000	$ 4,800,000	$ 1,400,000
Total fair value of options vested				9,100,000	3,900,000	2,300,000
Compensation expense recognized				$ 15,823,000	$ 9,218,000	$ 2,655,000
Expected dividend yield rate				0.00%	0.00%	0.00%
Total unrecognized compensation cost				$ 20,900,000	$ 12,100,000
Weighted-average period of recognition				2 years 9 months 18 days	2 years 9 months 18 days
Internal Use Software Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Capitalized stock based compensation expense				$ 200,000	$ 100,000	$ 0
Employee Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized				$ 1,600,000	$ 3,400,000
Sale of shares				1,131,028	1,092,421
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance				1,506,000	947,000
Stock option plan, number of shares granted				808,000	947,342
Vesting starting period				2014-08
Vesting ending period				2017-08
Stock option plan, number of additional shares available for grant					372,342
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance				12,795,000	11,408,000
Outstanding stock options				180,000
Performance-based Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized				$ 800,000
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate				1.95%	2.01%	2.06%
Expected volatility				39.63%	46.68%	55.80%
Expected term (in years)				6 years 2 months 23 days	6 years 29 days	6 years 29 days
MEC 2009 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares outstanding				527,770
2013 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional common stock shares reserved for issuance			3,000,000
Common stock reserved for issuance			4,500,000
Stock options vesting period			4 years
Stock option plan, number of shares granted				0
2013 Equity Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance			8,044,829
Stock options granted, expiration period			10 years
2013 Equity Incentive Plan | End of One Year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting award percentage			25.00%
2013 Equity Incentive Plan | Monthly Over the Remaining Three Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting award percentage			75.00%
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance		1,197,342					947,342
2014 Equity Incentive Plan | Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plan, number of shares granted		1,197,342
2015 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance		11,400,000		12,006,000
Stock options vesting period		4 years
2015 Equity Incentive Plan | Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period		4 years
Stock option plan, number of shares granted				250,000
Outstanding RSUs				783,228
2015 Equity Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance		15,439,334
Stock options granted, expiration period		10 years
2015 Equity Incentive Plan | End of One Year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting award percentage		25.00%
2015 Equity Incentive Plan | End of One Year | Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting award percentage		25.00%
2015 Equity Incentive Plan | Monthly Over the Remaining Three Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting award percentage		75.00%
2015 Equity Incentive Plan | Quarterly Over the Remaining Three Years | Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting award percentage		75.00%
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	1,000,000			1,000,000
Minimum annual increase included in common stock reserved for future issuance as of first day of each fiscal year	5,000,000
Minimum percentage of annual increase included in common stock reserved for future issuance as of last day of immediately preceding fiscal year	2.00%
Terms of shares available for issuance				The number of shares of common stock available for sale under the Company’s ESPP will also include an annual increase on the first day of each fiscal year beginning on January 1, 2016, equal to the least of (i) 5,000,000 shares (ii) 2% of the common stock as of the last day of the immediately preceding fiscal year or (iii) such other amount as the Company’s board of directors may determine.
Maximum deductible value of shares available for employee to purchase per calendar year	$ 25,000
Maximum percentage in payroll deductions to acquire shares of common stock	15.00%
Maximum number of shares available for employee to purchase per offering period	2,000
Term of offering period				Employees are offered shares bi-annually through two six month offering periods, which begin on the first trading day on or after May 15 and November 15 of each year. The first offering period began on November 16, 2015.
Risk-free interest rate				0.33%
Expected volatility				33.84%
Expected term (in years)				6 months
Expected dividend yield rate				0.00%