Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Reconciliation

The differences between the effective income tax rate and the statutory tax rates during the years ended 2019, 2018 and 2017 are as follows (in thousands):

	Year Ended December 31,
	2019			2018			2017
Net loss before tax	$	(213,256	)	$	(98,418	)	$	(70,430	)
Statutory combined U.S. federal and state tax rate	21.00		%	21.00		%	34.00		%
Statutory federal and state taxes	(44,784		)	(20,668		)	(23,946		)
Increase (decrease) in taxes recoverable resulting from:
Effect of change in valuation allowance	52,719			25,959			(4,154		)
Non-deductible share-based compensation	1,810			884			695
Tax deductions for share-based compensation	(6,917		)	(2,924		)	(80		)
Tax credits	(8,621		)	(5,130		)	(2,563		)
Write off of Methylgene US Inc. net operating loss	—			—			307
Change in tax rate	—			—			303
Tax Cuts and Jobs Act	—			—			28,569
Uncertain tax positions	2,143			1,283			646
Return to provision and other true-ups	(60		)	375			394
Non-deductible officers' compensation	3,527			179			—
Other differences	183			42			(171		)
Income tax benefit	$	—		$	—		$	—

Schedule of Deferred Tax

The following table summarizes the significant components of our deferred tax assets (in thousands):

	December 31,
	2019			2018
Deferred tax assets:
Tangible and intangible depreciable assets	$	6,978		$	8,123
Stock compensation	12,321			6,515
Provisions	934			1,020
Other, net	35			—
Lease liability	137			—
Net operating loss carry forwards	116,345			74,721
Capital loss carryforward	178			178
Canada scientific research and experimental development expenditures	5,471			5,467
U.S. research and development tax credits	17,080			10,613
Total gross deferred tax assets	159,479			106,637
Less valuation allowance	(159,357		)	(106,637		)
Net deferred tax assets	$	122		$	—
Deferred tax liabilities:
Right-of-use Asset	$	(122	)	$	—
Net deferred income taxes	$	—		$	—

Schedule of Expiration of NOLs

The NOLs expire as follows (in thousands):

	US				Canada
	Federal		State		Federal		Provincial
Expires in:
2030	$	—	$	—	$	4,830	$	4,907
2031	—		—		7,059		7,066
2032	—		—		13,308		12,433
2033	2,225		2,232		18,623		19,385
2034	7,276		22,162		32,401		31,809
2035	53,359		52,950		1,084		1,084
2036	23,379		—		777		777
2037	65,509		—		697		697
2038	—		3,817		—		—
2039	—		—		274		274
Does not expire	300,763		—		—		—
	$	452,511	$	81,161	$	79,053	$	78,432

Schedule of Unrecognized Tax Positions

A reconciliation of the beginning and ending amounts of unrecognized tax positions are as follows (in thousands):

	Federal							Provincial/State
	December 31,							December 31,
	2019		2018		2017			2019		2018		2017
Unrecognized tax positions, beginning of year	$	2,617	$	1,693	$	1,095		$	8,010	$	7,556	$	7,333
Gross increase — current period tax positions	1,651		924		588			638		454		227
Gross decrease — prior period tax positions	—		—		—			—		—		(3		)
Gross increase — prior period tax positions	—		—		11			—		—		—
Expiration of statute of limitations	—		—		(1		)	—		—		(1		)
Unrecognized tax positions, end of year	$	4,268	$	2,617	$	1,693		$	8,648	$	8,010	$	7,556