Stock Options, Stock Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unamortized Stock Compensation Expense [Abstract]
Unamortized stock compensation expense	$ 10,076,261
Period for recognition	1 year 4 months 6 days
The Plans [Member] | Stock Options [Member]
Number of Shares [Roll Forward]
Options outstanding, beginning balance (in shares)	4,302,267	2,445,711	1,993,301
Granted (in shares)	1,211,400	1,902,609	452,410
Exercised (in shares)	(63,639)	(4,753)	0
Forfeited (in shares)	(133,517)	(30,640)	0
Expirations (in shares)		(10,660)
Options outstanding, ending balance (in shares)	5,316,511	4,302,267	2,445,711
Vested and expected to vest (in shares)	5,235,931	4,213,091	2,408,395
Exercisable (in shares)	3,027,112	1,857,077	1,413,335
Weighted Average Exercise Price [Roll Forward]
Options outstanding, beginning balance (in dollars per share)	$ 5.19	$ 3.13	$ 2.00
Granted (in dollars per share)	8.09	7.87	8.15
Exercised (in dollars per share)	4.62	0.23	0
Forfeited (in dollars per share)	5.79	7.98	0
Expirations (in dollars per share)		8.28
Options outstanding, ending balance (in dollars per share)	5.84	5.19	3.13
Vested and expected to vest (in dollars per share)	5.80	5.14	3.12
Exercisable (in dollars per share)	$ 4.41	$ 2.83	$ 2.46
Remaining Contractual Life and Aggregate Intrinsic Value [Abstract]
Options outstanding, weighted average remaining contractual life	7 years 7 months 6 days	8 years 1 month 20 days	8 years 2 months 5 days
Options outstanding, aggregate intrinsic value	$ 35,599,646	$ 31,659,550	$ 6,247,407
Vested and expected to vest, weighted average contractual life	7 years 6 months 29 days	8 years 1 month 13 days	8 years 2 months 1 day
Vested and expected to vest, aggregate intrinsic value	$ 35,246,927	$ 31,202,132	$ 6,175,025
Exercisable, weighted average contractual life	6 years 9 months 4 days	7 years 18 days	7 years 10 months 10 days
Exercisable, aggregate intrinsic value	$ 24,559,384	$ 17,952,965	$ 4,162,373