Stock-Based Compensation - Stock Options & RSU (Details)	1 Months Ended	9 Months Ended
	Sep. 30, 2015 shares	Dec. 31, 2015 plan $ / shares shares	Dec. 31, 2014 shares
Employee Benefit Plans
Number of stock incentive plans | plan		2
Stock options
Number of Options
Options outstanding at the beginning of the period (in shares)		2,199,000
Granted (in shares)		1,808,000
Exercised (in shares)		(235,000)
Forfeited (in shares)		(79,000)
Expired (in shares)		(376,000)
Options outstanding at the end of the period (in shares)		3,317,000
Weighted Average Exercise Price Per Share
Options outstanding at the beginning of the period (in dollars per share) | $ / shares		$ 1.83
Granted (in dollars per share) | $ / shares		2.35
Exercised (in dollars per share) | $ / shares		1.57
Forfeited (in dollars per share) | $ / shares		1.82
Expired (in dollars per share) | $ / shares		2.36
Options outstanding at the end of the period (in dollars per share) | $ / shares		$ 2.07
Restricted stock units
Weighted Average Exercise Price Per Share
Number of shares of common stock receivable upon vesting of each RSU		1
Number of Shares
RSUs outstanding at the beginning of the period (in shares)		194,000
Granted (in shares)		63,000
Vested (in shares)		(66,000)
Forfeited (in shares)		(18,000)
RSUs outstanding at the end of the period (in shares)		173,000
2007 Plan
Employee Benefit Plans
Shares of common stock available for grant		902,000
Vested and expected to vest at the end of the period (in shares)		2,900,000	2,200,000
2007 Plan | CEO
Employee Benefit Plans
Expected life - years	7 years 3 months 18 days
Risk-free interest rate (as a percent)	1.90%
Expected volatility of common stock (as a percent)	0.48%
Dividend yield (as a percent)	0.00%
Number of Options
Granted (in shares)	1,350,000