Stockholders' equity (deficit) (Tables)

3 Months Ended

Mar. 31, 2018

Stockholders' equity (deficit)

Schedule of stockholder's equity

				Additional		Accumulated				Stockholders’
	Common Stock			Paid-in		Other Comprehensive		Accumulated		Equity
	Shares	Amount		Capital		Income (Loss)		Deficit		(Deficit)
Balance at December 31, 2016	1,294,352	$	1	$	3,551	$	—	$	(59,171)	$	(55,619)
Change	21,470,665		2		164,467		(149)		(38,707)		125,613
Balance at December 31, 2017	22,765,017		3		168,018		(149)	$	(97,878)		69,994
Change	104,945		—		1,000		(13)		(14,434)		(13,447)
Balance at March 31, 2018	22,869,962	$	3	$	169,018	$	(162)	$	(112,312)	$	56,547

Schedule for number of common stock reserved for conversion of outstanding Preferred Stock and for the exercise of outstanding stock options and warrants

	March 31,	December 31,
	2018	2017
Warrants	110,365	110,365
Stock options	3,905,845	3,205,485
	4,016,210	3,315,850