Share Based Awards (Tables)

3 Months Ended

Mar. 31, 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	3,200,982		4.04
Vested	(3,001,189)		4.60
Forfeitures	(533,623)		4.67
Unvested, March 31, 2020	12,305,236	$	5.07

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, March 31, 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	738,233
Restricted stock units granted	(1,470,300)	—
Performance stock units granted	(1,005,000)	—
Exercised	—	(29,797)		3.93
Stock options canceled	71,058	(71,058)		5.41
Restricted stock units canceled	533,623	—
Balance—March 31, 2020	4,075,082	2,798,122	$	5.18		4.50	$	472
Vested and exercisable—March 31, 2020		2,432,496	$	5.28		3.93	$	468
Vested and expected to vest(1)—March 31, 2020		2,739,242	$	5.19		4.42	$	472

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

Schedule of stock-based compensation expense recognized

	Three Months Ended
	March 31,
	2020		2019
Cost of revenue	$	898	$	1,541
Research and development		3,059		4,111
Sales and marketing		2,073		2,274
General and administrative		1,543		2,364
Total	$	7,573	$	10,290

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

	Three Months Ended
	March 31,
	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

	Three Months Ended
	March 31,
	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	$	0.7	2.3
Restricted stock units		45.8	2.7
Performance stock units		2.3	2.1
ESPP		3.2	1.9
Total	$	52.0