Stockholders' Equity (Deficit) (Tables)

12 Months Ended

Dec. 31, 2018

Schedule of Reserved Shares of Common Stock for Issuance

At December 31, 2018, the Company had reserved shares of common stock for issuance as follows (in thousands):

	As of December 31, 2018
Common stock awards granted under equity incentive plans		20,057
Common stock awards available for grant under equity incentive plan		13,239
Total reserved shares of common stock		33,296

Schedule of Activity Under Equity Incentive Plan

The following table summarizes the Company’s stock option activities under the 2008 Plan and 2017 Plan (in thousands, except per share data):

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Weighted Average Grant Date Fair Value Per Share		Aggregate Intrinsic Value
Balance, December 31, 2017		26,336		$	4.59		6.4		—
Granted		1,040			52.32		—	$	22.96
Exercised		(10,315	)		2.90		—		—
Forfeited and expired		(690	)		6.79		—		—
Balance, December 31, 2018 - outstanding		16,371		$	8.59		6.8		—	$	384,383
Options exercisable at December 31, 2018		8,849		$	4.72		5.6		—	$	230,254

Schedule of Share-based Compensation Expense Included in Consolidated Statements of Operations

The following table shows total stock-based compensation expense included in the accompanying Consolidated Statements of Operations for the years ended December 31, 2018, 2017 and 2016 (in thousands):

	Years Ended December 31,
	2018		2017		2016
Cost of platform revenue	$	97	$	81	$	224
Cost of player revenue		469		145		136
Research and development		18,538		4,714		2,766
Sales and marketing		10,459		2,817		2,292
General and administrative		8,111		3,196		2,788
Total stock-based compensation	$	37,674	$	10,953	$	8,206

Summary of Assumptions Used to Value Stock-Based Awards Granted

The assumptions used to value stock-based awards granted during the years ended December 31, 2018, 2017 and 2016 are as follows:

	Years Ended December 31,
	2018		2017		2016
Dividend rate		—		—		—
Expected term (in years)	5.3 - 6.8		5.3 - 6.5		5.3 - 6.5
Risk-free interest rate	2.32 - 2.88%		1.87 - 2.25%		1.33 - 1.95%
Expected volatility	38 - 40%		39 - 44%		44 - 46%
Fair value of common stock		—	$2.56 - $18.46		$5.64 - $6.60

The Company valued the convertible preferred stock warrants using the following assumptions:

Summary of Restricted Stock Unit Activity

Pursuant to the 2017 Plan, the Company issued restricted stock units to employees. Restricted stock unit activity for the year ended December 31, 2018 is as follows (in thousands, except per share data):

	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Balance, December 31, 2017		272		$	43.55
Awarded		3,827			48.26
Released		(267	)		42.95
Forfeited		(146	)		43.14
Balance, December 31, 2018 - outstanding		3,686		$	48.50

Convertible Preferred Stock Warrants

Summary of Assumptions Used to Value Stock-Based Awards Granted

	Years Ended December 31,
	2017		2016
Dividend rate		—		—
Expected term (in years)	3.0 - 9.7		3.2 - 3.9
Risk-free interest rate	1.5 - 2.3%		0.7 - 1.6%
Expected volatility	44 - 51%		46 - 48%