Stock Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Options, RSUs Activity under 2014 Equity Incentive Plan and 2016 Inducement Plan and Related Information

The following table summarizes option and RSUs activity under the Company’s 2014 Plan, 2016 Plan and 2019 Plan, and related information:

	Shares Available for Grant	Stock Options Outstanding	Weighted- Average Exercise Price		Number of RSU Shares	Weighted- Average Grant Date Fair Value
Balance—December 31, 2022	1,490,462	2,921,925	$	28.13	3,094,396	$	37.39
Additional options authorized	2,141,330	—	—		—	—
Common stock awards for services	(21,965)	—	—		—	—
RSUs granted	(4,028,424)	—	—		4,028,424	10.52
RSUs vested	—	—	—		(989,314)	36.43
Options granted	(680,788)	680,788	12.60		—	—
Options exercised	—	(27,903)	4.29		—	—
Repurchases of common stock under employee incentive plans	322,163	—	—		—	—
RSUs forfeited	1,126,731	—	—		(1,126,731)	22.92
Options forfeited	265,395	(265,395)	26.90		—	—
Options expired	254,207	(254,207)	27.13		—	—
Balance—December 31, 2023	869,111	3,055,208	$	25.21	5,006,775	$	19.02

Summary of Options Outstanding and Exercisable Vested or Expected to Vest

Options outstanding that have vested and are expected to vest at December 31, 2023 are as follows:

	Number of Shares Issued (In thousands)	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value (In thousands)
Vested	1,786	$	26.21	6.27	$	1,751
Expected to Vest	1,191	23.56		8.59	530
Total	2,977				$	2,281

Summary of Weighted-Average Assumptions Used to Estimate Fair Value of Share-Based Awards

The estimated fair values of employee stock options and ESPP shares were estimated using the Black-Scholes option pricing model based on the following weighted average assumptions:

	Year Ended December 31,
	2023		2022		2021
Employee stock options
Expected term (in years)	5.61		5.96		5.94
Expected volatility	77.86	%	77.62	%	77.70	%
Risk-free interest rate	3.67	%	2.74	%	0.80	%
Expected dividend yield	—	%	—	%	—	%
Employee stock purchase plan
Expected term (in years)	0.5		0.5		0.5
Expected volatility	75.91% – 93.38%		67.79% – 77.88%		53.10% – 67.79%
Risk-free interest rate	5.26% – 5.47%		2.51% – 4.76%		0.09% – 0.19%
Expected dividend yield	—	%	—	%	—	%

Summary of Expense Relating to Employee and Nonemployee Stock-Based Payment Awards from Stock Options and RSUs

The following table summarizes stock-based compensation expense relating to employee and nonemployee stock-based awards for the years ended December 31, 2023, 2022 and 2021, included on the consolidated statements of operations as follows (in thousands):

	Year Ended December 31,
	2023		2022		2021
Cost of testing services	$	1,854	$	1,529	$	2,358
Cost of product	1,165		1,120		579
Cost of patient and digital solutions	1,377		1,331		728
Research and development	6,556		7,391		7,126
Sales and marketing	12,470		14,403		10,887
General and administrative	25,664		20,779		14,403
Total	$	49,086	$	46,553	$	36,081