Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity

A summary of the Company’s stock option activity under the 2012 Stock Plan (as amended and restated, the “2012 Plan”) and the 2018 Incentive Award Plan (the “2018 Plan”) and related information is as follows:

		Options Outstanding
	Shares Available for Grant	Shares Subject to Options Outstanding	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
	(unaudited)
						(in thousands)
Balance as of December 31, 2020	1,819,223	3,101,181	$	15.80	6.9	$	350,670
2018 Plan annual increase(1)	3,689,000	—
Granted	(60,677)	60,677	142.73
Exercised	—	(371,711)	14.34
Canceled	42,956	(86,241)	47.02
Restricted stock units granted	(177,166)	—	—
Restricted stock units canceled	94,075	—	—
Market-based restricted stock units canceled	558,254	—	—
Performance-based restricted stock units granted	(52,917)	—	—
Performance-based restricted stock units canceled	15,304	—	—
Balance as of June 30, 2021	5,928,052	2,703,906	$	17.86	6.5	$	288,749
Vested and Exercisable as of June 30, 2021		2,091,339	$	9.16	6.1	$	240,569

(1)Effective as of January 1, 2021, an additional 3,689,000 shares of common stock became available for issuance under the 2018 Plan, as a result of the operation of an automatic annual increase provision therein.

A summary of the Joint Venture's stock option activity under the AMEA 2020 Plan and related information is as follows:

		Options Outstanding
	Shares Available for Grant	Shares Subject to Options Outstanding	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
	(unaudited)
						(in thousands)
Balance as of December 31, 2020	542,220	4,053,335	$	0.58	9.6	$	—
Granted	(382,223)	382,223	0.58
Exercised	—	(91,109)	0.58
Canceled	92,412	(92,412)	0.58
Balance as of June 30, 2021	252,409	4,252,037	$	0.58	9.2	$	—
Vested and Exercisable as of June 30, 2021		2,352,180	$	0.58	9.1	$	—

Schedule of Restricted Stock Activity

A summary of the Company’s restricted stock unit activity excluding the performance-based and market-based restricted stock units under the 2012 Plan and the 2018 Plan and related information is as follows:

	Restricted Stock Units Outstanding	Weighted-Average Grant Date Fair Value
	(unaudited)
Balance as of December 31, 2020	1,118,655	$	92.89
Granted	177,166	154.94
Vested and released	(46,376)	80.32
Canceled	(94,075)	92.67
Balance as of June 30, 2021	1,155,370	$	102.93

A summary of the Company’s performance-based restricted stock unit activity under the 2018 Plan and related information is as follows:

	Performance-based Restricted Stock Units Outstanding	Weighted-Average Grant Date Fair Value
	(unaudited)
Balance as of December 31, 2020	377,922	$	113.40
Granted	52,917	135.94
Canceled	(15,304)	113.40
Balance as of June 30, 2021	415,535	$	116.27

A summary of the Company’s market-based restricted stock unit activity under the 2018 Plan and related information is as follows:

	Market-based Restricted Stock Units Outstanding	Weighted-Average Grant Date Fair Value
	(unaudited)
Balance as of December 31, 2020	3,391,148	$	67.00
Vested and released	(572,130)	70.58
Canceled (1)	(558,254)	70.58
Balance as of June 30, 2021	2,260,764	$	65.20

(1)Represented shares withheld by the Company for MSU holders' tax obligation upon release of vested MSUs.

Schedule of Performance-based Restricted Stock Units Vesting Conditions

The following table presents additional information relating to each MSU award:

Tranche	Price Goal	Number of RSUs
Tranche 1	$120 per share	565,192
Tranche 2	$150 per share	565,191
Tranche 3	$200 per share	565,191

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan

The following table presents the effect of employee and non-employee related stock-based compensation expense including the Joint Venture:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
	(unaudited)
	(in thousands)
Cost of precision oncology testing	$	873	$	407	$	1,640	$	710
Research and development expense	4,564		2,622		8,864		4,986
Sales and marketing expense	3,438		2,167		6,318		3,965
General and administrative expense	25,632		20,619		72,754		22,492
Total stock-based compensation expense	$	34,507	$	25,815	$	89,576	$	32,153

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The grant date fair value of stock options was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions including the Joint Venture:

	Three Months Ended June 30,		Six Months Ended June 30,
	2021	2020	2021	2020
	(unaudited)
Expected term (in years)	5.49 – 6.04	5.50 – 6.10	5.49 – 6.04	5.50 – 6.10
Expected volatility	63.6% – 66.7%	66.5% – 68.5%	63.6% – 66.7%	66.5% – 73.3%
Risk-free interest rate	0.3% – 1.1%	0.4% – 0.4%	0.3% – 1.1%	0.4% – 1.6%
Expected dividend yield	—%	—%	—%	—%

The grant date fair value of the stock purchase right granted under the ESPP was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions:

	Three and Six Months Ended June 30,
	2021	2020
	(unaudited)
Expected term (in years)	0.5	0.5
Expected volatility	50.8%	73.2%
Risk-free interest rate	—%	0.2%
Expected dividend yield	—%	—%