Stock Award Plans (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Award Plans

The following table summarizes information about the Company’s stock-based award plans as of December 31, 2019:

	Outstanding Options		Outstanding Restricted Stock Units		Shares Available for Future Issuance
2004 Equity Incentive Plan		451,149		—		—
2013 Equity Incentive Plan		4,714,169		393,309		—
2018 Equity Incentive Plan		8,934,586		663,738		4,710,565
2004 Non-Employee Directors’ Stock Option Plan		35,777		—		—
Total		14,135,681		1,057,047		4,710,565

Stock Based Compensation Expense Recognized in Accompanying Consolidated Statements of Operations by Category

Total stock-based compensation expense recognized in the accompanying consolidated statements of operations is included in the following categories (in thousands):

	Year Ended December 31,
	2019		2018
Cost of goods sold	$	601	$	379
Research and development		356		1,203
Selling, general and administrative		4,508		5,275
Cost of revenue — collaborations and services		738		—
Total	$	6,203	$	6,857

Assumptions Used to Calculate Fair Value of Employee Stock Options

The Company calculated the fair value of employee stock options granted during the years ended December 31, 2019 and 2018 using the following assumptions:

	Year Ended December 31,
	2019		2018
Risk-free interest rate	1.52% — 2.51%		2.63% — 3.11%
Expected lives	6.20 — 9.37 years		5.90 — 7.19 years
Volatility	93.05% — 94.25%		92.68% — 93.62%
Dividends		—		—

Summary of Stock Options Outstanding

The following table summarizes information about stock options outstanding:

	Number of Shares			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value ($000)
Outstanding at January 1, 2019		10,976,118		$	5.75		7.83	$	—
Granted		5,613,253			1.32
Exercised		(67,461	)		1.10
Forfeited		(1,395,644	)		2.25
Expired		(990,585	)		17.07
Outstanding at December 31, 2019		14,135,681		$	3.09		7.84	$	182
Exercisable at December 31, 2019		4,554,661		$	6.20		6.00	$	86

Summary of Restricted Stock Unit Activity

A summary of restricted stock unit activity for the year ended December 31, 2019 is presented below:

	Number of Shares			Weighted Average Grant Date Fair Value per Share
Outstanding at January 1, 2019		691,266		$	3.72
Granted		1,293,690			1.42
Vested		(804,105	)		2.33
Forfeited		(123,804	)		2.06
Outstanding at December 31, 2019		1,057,047			2.16