Stock Option Plan (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Share-based Compensation Expenses

During the years ended December 31, 2016, 2015 and 2014, the Company recorded employee share-based compensation expense from continuing operations of $1,573, $1,974 and $168, respectively. The Company recorded non-employee share-based compensation expense from continuing operations of $0 during the years ended December 31, 2016 and 2015, and $9 during the year ended December 31, 2014. Total share-based compensation expense included in the consolidated statements of operations is as follows:

	Year Ended December 31,
	2016		2015		2014
Research and development	$	477	$	541	$	98
General and administrative		1,096		1,433		79
Discontinued operations		—		410		—
	$	1,573	$	2,384	$	177

Fair Value of Option Grant Estimated on Grant Date Using Black-Scholes Option-pricing Model

The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, using the following weighted average assumptions:

	Year Ended December 31,
	2016			2015			2014
Estimated dividend yield		0.00	%		0.00	%		0.00	%
Expected volatility		75.08	%	65.96-102.77%				102.77	%
Risk-free interest rate		1.32	%	1.48-1.81%				1.88	%
Expected life of options (in years)		5.72		5.1-5.9				6.00
Weighted-average fair value per share	$	11.47		$	6.83		$	6.59 - 7.06

Summary of Stock Option Activity

Stock option activity for the periods indicated is as follows:

	Shares Available for Grant			Shares Subject to Outstanding Options			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Options outstanding as of December 31, 2013		79,722			209,527		$	0.63
Additional shares reserved under plan		416,666			—
Options granted		(211,500	)		211,500			1.12
Options forfeited		17,083			(17,083	)		0.71
Options exercised		—			(67,431	)		0.70
Options outstanding as of December 31, 2014		301,971			336,513		$	0.91
Additional shares reserved under plan		416,666			—
Options granted		(366,909	)		366,909			8.80
Options forfeited		54,165			(54,165	)		3.70
Options exercised		—			(191,023	)		2.45
Options outstanding as of December 31, 2015		405,893			458,234		$	6.26
Additional shares reserved under plan		611,272			—
Options granted		(405,624	)		405,624			16.06
Options forfeited		3,666			(7,395	)		6.62
Options exercised		—			(31,333	)		1.11
Options outstanding as of December 31, 2016		615,207			825,130		$	11.27		8.54	$	12,994
Vested and expected to vest as of    December 31, 2014					279,505		$	0.88		8.39	$	1,996
Exercisable as of December 31, 2014					92,833		$	0.54		6.44	$	694
Vested and expected to vest as of    December 31, 2015					430,730		$	6.16		8.80	$	5,102
Exercisable as of December 31, 2015					232,827		$	4.27		8.38	$	3,196
Vested and expected to vest as of    December 31, 2016					766,402		$	10.95		8.49	$	12,314
Exercisable as of December 31, 2016					303,162		$	7.32		7.53	$	5,974