Stockholders' Equity - Authorized Shares (Details) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Common stock, authorized (in shares)	200,000,000	110,000,000
Preferred stock, authorized (in shares)	10,000,000	76,894,620
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001