Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Reconciliation of liabilities measured at fair value using significant unobservable inputs

The following table provides a reconciliation of liabilities measured at fair value using significant unobservable inputs (Level 3) for the year ended December 31, 2017 and 2018 (in thousands):

	Level 3 Liabilities
Balance at December 31, 2016	$	—
Transfer from equity		29,413
Changes in fair value		(12,044	)
Exercises		(2,311	)
Transfer to equity		(15,058	)
Balance at December 31, 2017		—
Contingent consideration liability recorded upon acquisition of SafeOp		3,200
Settlement of milestone #1		(1,446	)
Change in fair value measurement		846
Balance at December 31, 2018	$	2,600

Summary of weighted average assumptions used to compute stock-based compensation costs for stock options granted

The weighted average assumptions used to compute the stock-based compensation costs for the stock options granted during the years ended December 31, 2018 and 2017 are as follows:

	Year Ended December 31,
	2018			2017
Risk-free interest rate		2.85	%		2.01	%
Expected dividend yield		—			—
Weighted average expected life (years)		6.08			6.02
Volatility		78.54	%		78.52	%

Summary of compensation cost for stock-based compensation arrangements

The compensation cost that has been included in the Company’s consolidated statement of operations for all stock-based compensation arrangements is detailed as follows (in thousands):

	Year Ended December 31,
	2018		2017
Cost of revenues	$	73	$	40
Research and development		482		206
Sales, general and administrative		4,749		3,735
Total	$	5,304	$	3,981

Computation of Basic and Diluted Loss Per Share

The following table sets forth the computation of basic and diluted loss per share (in thousands, except per share data):

	Year Ended December 31,
	2018			2017
	Net loss attributable to common shareholders			Continuing operations			Discontinued operations
Numerator:
Net (loss) income, basic	$	(42,463	)	$	(4,540	)	$	2,246
Change in fair value of warrants		—			12,044			—
Net (loss) income, diluted	$	(42,463	)	$	(16,584	)	$	2,246
Denominator:
Weighted average common shares outstanding		35,402			12,827			12,827
Weighted average unvested common shares subject to repurchase		(87	)		(39	)		(39	)
Weighted average common shares outstanding - basic		35,315			12,788			12,788
Dilutive impact of warrants		—			494			494
Weighted average common shares outstanding - diluted		35,315			13,282			13,282
Basic net (loss) income per share	$	(1.20	)	$	(0.36	)	$	0.18
Diluted net (loss) income per share	$	(1.20	)	$	(1.25	)	$	0.17

Weighted-average anti-dilutive securities not included in diluted net loss per share

The anti-dilutive securities not included in diluted net loss per share were as follows calculated on a weighted average basis (in thousands):

	Year Ended December 31,
	2018		2017
Options to purchase common stock		330		3,156
Warrants to purchase common stock		1,860		1,204
Series A convertible preferred stock		2,141		3,829
Unvested restricted stock awards		87		39
Convertible notes		761		—
		5,179		8,228