Stockholders' equity (Tables)

6 Months Ended

Jun. 30, 2018

Stockholders Equity Note [Abstract]

Schedule of Company Recognized Stock Compensation Expense

For the three and six months ended June 30, 2018 and 2017, the Company recognized share-based compensation expense as follows:

	Three Months Ended June 30,					Six Months Ended June 30,
	2018		2017			2018		2017
Cost of services	$	1,341	$	2,145		$	3,731	$	3,968
Research and development		61,080		52,777			130,551		110,555
General and administrative		140,158		160,419			292,340		312,895
Sales and marketing		11,311		(6,034	)		25,458		27,294
	$	213,890	$	209,307		$	452,080	$	454,712

Schedule of Warrants to Purchase Shares of Common Stock

Stock purchase warrants

At June 30, 2018 and December 31, 2017, the following warrants to purchase shares of common stock were outstanding:

				Outstanding at
Issuance	Exercise Price		Expiration	June 30, 2018 (1)		December 31, 2017 (1)
March 2008	$	19,763.50	March 2018		—		2
November 2009	$	197.75	November 2019		270		270
January 2010	$	197.75	January 2020		270		270
March 2010	$	197.75	March 2020		55		55
November 2011	$	197.75	November 2021		212		212
December 2011	$	197.75	December 2021		27		27
March 2012	$	2,747.50	March 2019		165		165
February 2015	$	165.00	February 2025		9,001		9,001
May 2015	$	165.00	May 2020		138,310		138,310
May 2016	$	32.81	May 2021		189,577		189,577
June 2016	$	32.81	May 2021		82,035		82,035
June 2017	$	19.50	June 2022		18,754		18,754
July 2017	$	17.25	July 2022		6,350		6,350
July 2017	$	12.50	July 2022		50,000		50,000
July 2017	$	10.63	July 2022		1,000,003		1,000,003
February 2018	$	4.06	February 2023		184,615		—
February 2018	$	3.25	February 2023		1,846,153		—
					3,525,797		1,495,031

(1) Warrants to purchase fractional shares of common stock resulting from the reverse stock split on January 17, 2018 were rounded up to the next whole share of common stock on a holder by holder basis.