Equity (Details) (USD $)	3 Months Ended
	Mar. 31, 2014 Plan		Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based compensation plans	3
Outstanding assumed options (in shares)	375,000
Additional shares authorized by Board of Directors (in shares)	4,000,000
Shares authorized (in shares)	26,500,000
Total unrecognized compensation expense	$ 18,212,000
Number of shares [Roll forward]
Outstanding, beginning of period (in shares)	15,375,960
Granted (in shares)	2,094,369
Exercised (in shares)	(317,193)
Unvested options forfeited (in shares)	(10,833)
Vested options expired (in shares)	0
Outstanding, end of period (in shares)	17,142,303
Vested at end of period (in shares)	8,777,850
Exercisable options, vested and expected to vest (in shares)	16,742,166	[1]
Weighted-Average Exercise Price [Roll forward]
Outstanding, weighted average exercise price, beginning of period (in dollars per share)	$ 2.46
Granted, weighted average exercise price (in dollars per share)	$ 7.29
Exercised, weighted average exercise price (in dollars per share)	$ 1.42
Unvested options forfeited weighted-average exercise price (in dollars per share)	$ 1.24
Vested options expired weighted-average exercise price (in dollars per share)	$ 0.00
Outstanding, weighted average exercise price, end of period (in dollars per share)	$ 3.07
Vested at end of period weighted average exercise price (in dollars per share)	$ 1.69
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 3.01	[1]
Stock options, additional disclosures [Abstract]
Vested at end of period weighted average remaining contractual term	6 years 9 months 18 days
Vested and expected to vest, weighted average remaining contractual term	7 years 8 months 12 days	[1]
Outstanding intrinsic value	55,171,947
Vested at end of period aggregate intrinsic value	38,950,079
Vested and expected to vest, aggregate intrinsic value	54,754,819	[1]
Exercised options, intrinsic value	1,977,000
Number of outstanding options (in shares)	17,142,303
Outstanding Options, weighted average remaining contractual term	7 years 9 months 18 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 3.07
Number of exercisable options (in shares)	8,777,850
Exercisable Options, weighted average exercise price (in dollars per share)	$ 1.69
Fair value options valuation assumptions [Abstract]
Expected volatility	64.10%		64.30%
Expected life (in years)	6 years		6 years
Expected dividend yield	0.00%		0.00%
Risk-free interest rate, minimum (in hundredths)	1.69%		0.98%
Risk-free interest rate, maximum (in hundredths)	1.96%		1.86%
Share-based Compensation [Abstract]
Share-based compensation expense	2,372,364		984,792
Weighted-average grant date fair value for options granted during the period (in dollars per share)	$ 4.23
Warrants, term	5 years
Warrants
Warrants, Number of Warrants [Roll Forward]
Warrants outstanding, beginning of period (in shares)	1,284,816
Warrants exercised (in shares)	(1,017,000)
Warrants outstanding, end of period (in shares)	267,816
Warrants, Weighted-Average Exercise Price per Warrant [Roll Forward]
Warrants outstanding, beginning of period (in dollars per share)	0.90
Warrants exercised (in dollars per share)	0.76
Warrants outstanding, end of period (in dollars per share)	1.44
Cost of Products Sold
Share-based Compensation [Abstract]
Share-based compensation expense	97,516		50,162
Research and Development
Share-based Compensation [Abstract]
Share-based compensation expense	159,686		75,978
Selling, General and Administrative
Share-based Compensation [Abstract]
Share-based compensation expense	2,115,162		858,652
$0.50 - $0.76
Stock options, additional disclosures [Abstract]
Exercise Price Range, lower range limit (in dollars per share)	$ 0.50
Exercise Price Range, upper range limit (in dollars per share)	$ 0.76
Number of outstanding options (in shares)	1,165,935
Outstanding Options, weighted average remaining contractual term	3 years 10 months 24 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 0.66
Number of exercisable options (in shares)	1,165,935
Exercisable Options, weighted average exercise price (in dollars per share)	$ 0.66
$0.87 - $1.35
Stock options, additional disclosures [Abstract]
Exercise Price Range, lower range limit (in dollars per share)	$ 0.87
Exercise Price Range, upper range limit (in dollars per share)	$ 1.35
Number of outstanding options (in shares)	6,364,011
Outstanding Options, weighted average remaining contractual term	7 years 4 months 24 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 1.20
Number of exercisable options (in shares)	4,791,313
Exercisable Options, weighted average exercise price (in dollars per share)	$ 1.20
$1.40 - $2.29
Stock options, additional disclosures [Abstract]
Exercise Price Range, lower range limit (in dollars per share)	$ 1.40
Exercise Price Range, upper range limit (in dollars per share)	$ 2.29
Number of outstanding options (in shares)	1,571,700
Outstanding Options, weighted average remaining contractual term	5 years 9 months 18 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 1.64
Number of exercisable options (in shares)	1,321,698
Exercisable Options, weighted average exercise price (in dollars per share)	$ 1.66
$2.33 - $3.75
Stock options, additional disclosures [Abstract]
Exercise Price Range, lower range limit (in dollars per share)	$ 2.33
Exercise Price Range, upper range limit (in dollars per share)	$ 3.75
Number of outstanding options (in shares)	2,042,318
Outstanding Options, weighted average remaining contractual term	8 years 6 months
Outstanding Options, weighted average exercise price (in dollars per share)	$ 2.75
Number of exercisable options (in shares)	605,964
Exercisable Options, weighted average exercise price (in dollars per share)	$ 2.77
$3.95 - $5.99
Stock options, additional disclosures [Abstract]
Exercise Price Range, lower range limit (in dollars per share)	$ 3.95
Exercise Price Range, upper range limit (in dollars per share)	$ 5.99
Number of outstanding options (in shares)	3,263,670
Outstanding Options, weighted average remaining contractual term	9 years
Outstanding Options, weighted average exercise price (in dollars per share)	$ 5.08
Number of exercisable options (in shares)	892,940
Exercisable Options, weighted average exercise price (in dollars per share)	$ 4.99
$6.02 - $8.34
Stock options, additional disclosures [Abstract]
Exercise Price Range, lower range limit (in dollars per share)	$ 6.02
Exercise Price Range, upper range limit (in dollars per share)	$ 8.34
Number of outstanding options (in shares)	2,734,669
Outstanding Options, weighted average remaining contractual term	9 years 3 months 18 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 7.09
Number of exercisable options (in shares)	0
Exercisable Options, weighted average exercise price (in dollars per share)	$ 0.00
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expenses expected to be recognized over a weighted-average period	2 years 4 months 24 days
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expenses expected to be recognized over a weighted-average period	2 years 6 months
Total unrecognized stock-based compensation related to time-based, nonvested restricted stock	$ 5,440,000
Number of Shares
Beginning Balance	576,550
Granted	448,864
Vested	(83,330)
Forfeited	0
Ending Balance	942,084
Weighted- Average Grant Date Fair Value
Beginning Balance (in dollars per share)	$ 5.53
Granted (in dollars per share)	$ 7.25
Vested (in dollars per share)	$ 5.07
Forfeited (in dollars per share)	$ 0.00
Beginning Balance (in dollars per share)	$ 6.39

[1] Includes forfeiture adjusted unvested shares.