Stock-Based Compensation - Option Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Number of shares
Balance at beginning of year (in shares)	462,000
Balance at end of year (in shares)	462,000		462,000
Exercisable (in shares)	421,667
Weighted-Average Exercise Price
Balance at beginning of year (in dollars per share)	$ 0.0003
Balance at end of year (in dollars per share)	0.0003		$ 0.0003
Exercisable at end of year (in dollars per share)	$ 0.0004
Weighted- Average Remaining Contractual Term (in Years)
Weighted-Average Remaining Contractual Term (in years)	5 years 3 months 26 days		5 years 6 months 26 days
Exercisable	5 years 1 month 21 days
Number of unvested options scheduled to vest
Unvested options (in shares)	40,333
Stock Options
Number of shares
Granted (in shares)		0
Stock Options | Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option life (in years)	10 years
Weighted- Average Remaining Contractual Term (in Years)
Aggregate intrinsic value of stock option awards outstanding	$ 3,807
Aggregate intrinsic value of stock option awards exercisable	$ 3,475