Employee Stock Benefit Plans - Restricted Stock Units - Activity (Details) - Restricted stock units	3 Months Ended
	Mar. 31, 2017 $ / shares shares
Number of Shares
Outstanding at the beginning of the period (in shares) | shares	1,299
Granted (in shares) | shares	1,195
Vested (in shares) | shares	(210)
Forfeited (in shares) | shares	(29)
Outstanding at the end of the period (in shares) | shares	2,255
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 12.53
Granted (in dollars per share) | $ / shares	16.71
Vested (in dollars per share) | $ / shares	12.85
Forfeited (in dollars per share) | $ / shares	13.80
Outstanding at the end of the period (in dollars per share) | $ / shares	$ 14.70