Stock Options, Stock Option Activity (Details)	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Unamortized Stock Compensation Expense [Abstract]
Unamortized stock compensation expense | $	$ 10,950,318
Period for recognition	1 year 5 months 16 days
The Plans [Member] | Stock Options [Member]
Number of Shares [Roll Forward]
Options outstanding, beginning balance (in shares) | shares	4,302,267
Granted (in shares) | shares	976,400
Exercised (in shares) | shares	(7,375)
Forfeited (in shares) | shares	(133,517)
Expirations (in shares) | shares	0
Options outstanding, ending balance (in shares) | shares	5,137,775
Vested and expected to vest (in shares) | shares	5,035,892
Exercisable (in shares) | shares	2,617,577
Weighted Average Exercise Price [Roll Forward]
Options outstanding, beginning balance (in dollars per share) | $ / shares	$ 5.19
Granted (in dollars per share) | $ / shares	7.56
Exercised (in dollars per share) | $ / shares	3.55
Forfeited (in dollars per share) | $ / shares	5.79
Expirations (in dollars per share) | $ / shares	0
Options outstanding, ending balance (in dollars per share) | $ / shares	5.62
Vested and expected to vest (in dollars per share) | $ / shares	5.58
Exercisable (in dollars per share) | $ / shares	$ 3.97
Remaining Contractual Life and Aggregate Intrinsic Value [Abstract]
Options outstanding, weighted average remaining contractual life	8 years
Options outstanding, aggregate intrinsic value | $	$ 23,960,058
Vested and expected to vest, weighted average contractual life	7 years 11 months 23 days
Vested and expected to vest, aggregate intrinsic value | $	$ 23,679,976
Exercisable, weighted average contractual life	7 years 1 month 6 days
Exercisable, aggregate intrinsic value | $	$ 16,226,531