Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Options to purchase common stock
Net Loss Per Share
Securities excluded from the computation of diluted weighted-average shares outstanding	3,564,447	2,411,898
Nonvested restricted stock units
Net Loss Per Share
Securities excluded from the computation of diluted weighted-average shares outstanding	248,093	248,093
Employee stock option plan
Net Loss Per Share
Securities excluded from the computation of diluted weighted-average shares outstanding	92,892	93,040
Settlement of short-term debt
Net Loss Per Share
Securities excluded from the computation of diluted weighted-average shares outstanding	85,352	126,621
Nonvested restricted stock awards
Net Loss Per Share
Securities excluded from the computation of diluted weighted-average shares outstanding	10,586
Warrants to purchase common stock
Net Loss Per Share
Securities excluded from the computation of diluted weighted-average shares outstanding		13,259