Stock-Based Compensation - Summary of Stock Option Activity (Details) - 2011 Equity Incentive Plan - Employee Stock Option shares in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, number of shares (in shares) | shares	984
Granted, number of shares (in shares) | shares	206
Forfeited or expired, number of shares (in shares) | shares	(886)
Options outstanding, number of shares (in shares) | shares	304	984
Options exercisable, number of shares (in shares) | shares	181
Options outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 21.78
Granted, weighted average exercise price (in dollars per share) | $ / shares	5.98
Forfeited or expired, weighted average exercise price (in dollars per share) | $ / shares	20.50
Options outstanding, weighted average exercise price (in dollars per share) | $ / shares	14.82	$ 21.78
Options exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 18.90
Options outstanding, weighted average remaining contractual life (Year)	8 years 18 days	7 years 8 months 12 days
Options exercisable, weighted average remaining contractual life (Year)	7 years 6 months 21 days