Share Based Awards (Tables)

6 Months Ended

Jun. 30, 2020

Share Based Awards

Schedule of restricted stock unit activity

	Restricted Stock Units
		Weighted-
		Average
	Number of	Grant Date
	Shares	Fair Value
Unvested, December 31, 2019	12,639,066	$	5.20
Granted	6,998,715		4.46
Vested	(4,439,725)		4.72
Forfeitures	(825,068)		5.00
Unvested, June 30, 2020	14,372,988	$	5.00

Schedule of PSU activity

	Performance Stock Units
		Weighted-
		Average
	Number of	Grant Date
	Shares	Fair Value
Unvested, December 31, 2019	—	$	n/a
Granted	1,005,000		3.27
Vested	—		n/a
Forfeitures	—		n/a
Unvested, June 30, 2020	1,005,000	$	3.27

Schedule of stock option activity under the 2008 Plan, 2014 Plan and 2015 Inducement Plan

		Options Outstanding
						Weighted-
	Number of					Average	Aggregate
	Shares		Weighted-			Remaining	Intrinsic
	Available	Number of	Average		Contractual		Value
	for Issuance	Shares	Exercise Price			Term (Years)	(In thousands)
Balance—December 31, 2019	1,301,881	2,898,977	$	5.17		4.89	$	1,556
Authorized	5,636,269	—
Stock options granted	—	—
Issuance of shares under Bonus Plans	(1,730,682)	—
Shares withheld from net settlement of restricted stock units	815,527
Restricted stock units granted	(5,268,033)	—
Performance stock units granted(1)	(1,005,000)	—
Exercised	—	(142,300)		3.51
Stock options canceled	83,813	(83,813)		5.53
Restricted stock units forfeited	825,068	—
Balance—June 30, 2020	658,843	2,672,864	$	5.25		4.12	$	1,424
Vested and exercisable—June 30, 2020		2,352,550	$	5.34		3.80	$	1,308
Vested and expected to vest(2)—June 30, 2020		2,625,187	$	5.26		4.08	$	1,408

(1) Performance stock units granted are reflected in the table as a decrease in the number of shares available for issuance at target achievement for tracking and reporting purposes but do not technically reduce shares available for issuance until earned.

(2) Options expected to vest reflect an estimated forfeiture rate.

Schedule of stock-based compensation expense recognized

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2020		2019		2020		2019
Cost of revenue	$	1,898	$	1,266	$	2,796	$	2,807
Research and development		5,284		3,625		8,343		7,736
Sales and marketing		3,389		2,064		5,462		4,338
General and administrative		2,935		1,902		4,478		4,266
Total	$	13,506	$	8,857	$	21,079	$	19,147

Schedule of assumptions used to estimate fair value of stock options granted to employees

	Six Months Ended
	June 30,
	2020	2019
Expected dividend yield	n/a	—
Risk-free interest rate	n/a	2.5%
Expected volatility	n/a	50%
Expected life (in years)	n/a	6.1

Schedule of assumptions used to estimate the fair value of Employee Stock Purchase Plan awards

	Six Months Ended
	June 30,
	2020	2019
Expected dividend yield	—	—
Risk-free interest rate	1.5%	2.5%
Expected volatility	45%	42%
Expected life (in years)	1.3	1.3

Schedule of unrecognized stock-based compensation expense and its remaining weighted-average recognition period

	Unrecognized		Remaining
	Stock-based		Weighted-Average
	Compensation		Recognition
	Expense		Period
	(in millions)		(in years)
Stock options	$	0.6	2.1
Restricted stock units		53.8	2.8
Performance stock units		2.9	1.9
ESPP		2.4	1.6
Total	$	59.7